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  • 1.
    Allison, James
    et al.
    University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    On the impact of coupling strength on complex system optimization for single-level formulations2005Ingår i: Proceedings of the ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference - 2005: presented at 2005 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference, September 24 - 28, 2005, Long Beach, California, USA /, New York: American Society of Mechanical Engineers , 2005, Vol. 2: 31st Design Automation Conference, s. 265-275Konferensbidrag (Refereegranskat)
    Abstract [en]

    Design of modern engineering products requires complexity management. Several methodologies for complex system optimization have been developed in response. Single-level strategies centralize decision-making authority, while multi-level strategies distribute the decision-making process. This article studies the impact of coupling strength on single-level Multi-disciplinary Design Optimization formulations, particularly the Multidisciplinary Feasible (MDF) and Individual Disciplinary Feasible (IDF) formulations. The Fixed Point Iteration solution strategy is used to motivate the analysis. A new example problem with variable coupling strength is introduced, involving the design of a turbine blade and a fully analytic mathematical model. The example facilitates a clear illustration of MDF and IDF and provides an insightful comparison between these two formulations. Specifically, it is shown that MDF is sensitive to variations in coupling strength, while IDF is not

  • 2.
    Allison, James
    et al.
    University of Michigan.
    Roth, Brian
    University of Michigan.
    Kokkolaras, Michael
    Kroo, Ilan
    Stanford University.
    Papalambros, Panos Y.
    University of Michigan.
    Aircraft family design using decomposition-based methods2006Ingår i: 11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference: [6 - 8 September 2006, Portsmouth, Virginia ; papers], Reston, Va.: American Institute of Aeronautics and Astronautics, AIAA , 2006, Vol. 1, s. 606-617Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper explores the use of decomposition-based methods for aircraft family design. The traditional approach in multidisciplinary design optimization is to decompose a problem along disciplinary lines. For aircraft family design problems, a more natural approach is decomposition by individual aircraft. This decomposition facilitates the concurrent development of several aircraft variants, providing substantial autonomy to individual aircraft development programs. Two decomposition-based methods are applied to the aircraft family problem: collaborative optimization and analytical target cascading. This paper marks the beginning of a collaborative effort to clarify the distinctions between these two methods, and to identify how these differences impact the relative performance and applicability of these methods. Initial product family results illustrate how decomposition-based methods can be applied to the aircraft family problem.

  • 3.
    Allison, James T.
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    On selecting single-level formulations for complex system design optimization2007Ingår i: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 129, nr 9, s. 898-906Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Design of complex products with several interacting subsystems or disciplinary analyses poses substantive challenges to both analysis and optimization, necessitating specialized solution techniques. A product or system may qualify as complex due to large scale or due to strong interactions. Single-level strategies for complex system optimization centralize decision-making authority, while multilevel strategies distribute the decision-making process. This article studies important differences between two popular single-level formulations: multidisciplinary feasible (MDF) and individual disciplinary feasible (IDF). Results presented aim at aiding practitioners in selecting between formulations. Specifically, while IDF incurs some computational overhead, it may find optima hidden to MDF and is more efficient computationally for strongly coupled problems; further MDF is sensitive to variations in coupling strength, while IDF is not. Conditions that lead to failure of MDF are described. Two new reproducible design examples are introduced to illustrate these findings and to provide test problems for other investigations

  • 4.
    Allison, James T.
    et al.
    Optimal Design Laboratory, Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Optimal Design Laboratory, Department of Mechanical Engineering, University of Michigan.
    Optimal partitioning and coordination decisions in decomposition-based design optimization2008Ingår i: Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - 2007: presented at 2007 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, September 4 - 7, 2007, Las Vegas, Nevada, USA, New York: American Society of Mechanical Engineers , 2008, Vol. 6, s. 709-718Konferensbidrag (Refereegranskat)
  • 5.
    Allison, James T.
    et al.
    MathWorks, Inc.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Optimal partitioning and coordination decisions in decomposition-based design optimization2009Ingår i: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 131, nr 8, s. 0810081-0810088Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The solution of complex system design problems using decomposition-based optimization methods requires determination of appropriate problem partitioning and coordination strategies. Previous optimal partitioning techniques have not addressed the coordination issue explicitly. This article presents a formal approach to simultaneous partitioning and coordination strategy decisions that can provide insights on whether a decompositionbased method will be effective for a given problem. Pareto-optimal solutions are generated to quantify tradeoffs between the sizes of subproblems and coordination problems as measures of the computational costs resulting from different partitioning and coordination strategies. Promising preliminary results with small test problems are presented. The approach is illustrated on an electric water pump design problem

  • 6.
    Allison, James
    et al.
    University of Michigan.
    Walsh, David
    University of Glasgow.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    Cartmell, Matthew
    University of Glasgow.
    Analytical target cascading in aircraft design2006Ingår i: 44th AIAA Aerospace Sciences Meeting and Exhibit: [Reno, Nevada, 9 - 12 January 2006], Reston, Va.: American Institute of Aeronautics and Astronautics, AIAA , 2006, s. 16112-16120Konferensbidrag (Refereegranskat)
    Abstract [en]

    Analytical Target Cascading (ATC) is a product development tool that computes component design specifications such that the final system design is consistent and meets design targets. ATC is useful for complex product design that must be approached by decomposition, and facilitates concurrent design activities. While ATC has been applied successfully to automotive design, this article introduces the application of ATC to aircraft design, and discusses how it can be congruent with current design practice. ATC is used to solve an aircraft design problem where several flight regimes are considered separately. ATC can be used to balance low-fidelity system analysis and component-level multidisciplinary design optimization (MDO) activities. Finally, ATC may be used to coordinate overall aircraft design, with MDO employed to solve tightly coupled disciplinary problems that exist within ATC elements.

  • 7.
    Cervantes, Michel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cupillard, Samuel
    Hydro-Québec Research’s Institute.
    Bance, Kevin
    National Institute for Applied Science.
    Kokkolaras, Michael
    McGill University.
    Shape optimization of a 3D slider with dimples2012Ingår i: Journal of Civil Engineering and Architecture, ISSN 1934-7359, E-ISSN 1934-7367, Vol. 6, nr 12, s. 1599-1607Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sliding contacts in laminar flow regimes have been investigated extensively in recent years. The results indicate the possibility to increase load carrying capacity in a slider bearing for more than 10% with the addition of dimples. Parametric studies have been performed to determine optimal size and position, with emphasis in the optimal shape and position of the dimple for an operating condition. In this article, the numerical analysis of a 2D textured slider bearing with a dimple is initially considered with an isothermal laminar fluid. Position, depth, width and convergence ratio are optimized, the results demonstrate the importance of the width and convergence ratio to increase load. Then, the numerical analysis of a 3D textured slider bearing with fore-region and extended channels at the outlet and on the sides of a pad is considered. The simulations are also carried out for a laminar isothermal flow. Three dimples are considered and their depth is optimized.

  • 8.
    Cervantes, Michel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Cupillard, Samuel
    Hydro-Québec Research’s Institute.
    Kokkolaras, Michael
    University of Michigan.
    Shape optimisation of a 3D slider with a dimple2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sliding contacts under laminar regime have been extensively investigated under the last years. The results indicate the possibility to increase load carrying capacity in a slider bearing with more than 10% with the addition of dimples. Parametric studies have been performed on size and position, while an optimisation to determine the true potential have not yet been examined. Of interest is the optimal shape of the dimple function of the operating condition and position. In the present work, the numerical analysis of a 2D textured slider bearing with fore-region is initially considered with an isothermal laminar fluid. One dimple is considered and the shape optimized for different operating conditions and positions. Then, the numerical analysis of a 3D textured slider bearing with fore-region and extended channels at the outlet and on the sides of a pad is considered with a temper-ature dependent fluid. The simulations are also carried out for a laminar flow. One dimple is considered and the shape optimized for different operating conditions and positions.

  • 9.
    Chan, Kuei-Yuan
    et al.
    University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    Skerlos, Steven J.
    University of Michigan.
    Mourelatoes, Zissimos
    Oakland University.
    Propagation of Uncertainty in Optimal Design of Multilevel Systems: Piston-Ring/Cylinder-Liner Case Study2004Ingår i: 2004 SAE world congress: Detroit, Michigan, March 8 - 11, 2004, Warrendale, Pa: Society of Automotive Engineers, Incorporated , 2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper proposes an approach for optimal design of multilevel systems under uncertainty. The approach utilizes the stochastic extension of the analytical target cascading formulation. The reliability of satisfying the probabilistic constraints is computed by means of the most probable point method using the hybrid mean value algorithm. A linearization technique is employed for estimating the propagation of uncertainties throughout the problem hierarchy. The proposed methodology is applied to a piston-ring/cylinder-liner engine subassembly design problem. Specifically, we assess the impact of variations in manufacturing-related properties such as surface roughness on engine attributes such as brake-specific fuel consumption. Results are compared to the ones obtained using Monte Carlo simulation.

  • 10.
    Cooper, Adam B.
    et al.
    University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    A Dual-Use Enterprise Context for Vehicle Design and Technology Valuation2004Ingår i: 2004 SAE world congress: Detroit, Michigan, March 8 - 11, 2004, Warrendale, Pa: Society of Automotive Engineers, Incorporated , 2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    Developing a new technology requires decision-makers to understand the technology's implications on an organization's objectives, which depend on user needs targeted by the technology. If these needs are common between two organizations, collaboration could result in more efficient technology development. For hybrid truck design, both commercial manufacturers and the military have similar performance needs. As the new technology penetrates the truck market, the commercial enterprise must quantify how the hybrid's superior fuel efficiency will impact consumer purchasing and, thus, future enterprise profits. The Army is also interested in hybrid technology as it continues its transformation to a more fuel-efficient force. Despite having different objectives, maximizing profit and battlefield performance, respectively, the commercial enterprise and Army can take advantage of their mutual needs. Developing the new technology in a dual-use context allows the Army to leverage the design and production capabilities of the commercial enterprise, while the enterprise increases its hybrid production volume with military trucks during the low demand phase of hybrid market penetration. This article describes the valuation of hybrid technology from both the enterprise and military perspectives using a previously developed enterprise decision model, which utilizes comprehensive vehicle simulation to drive decision-making. The enterprise is represented in a mathematical formulation that simultaneously optimizes initial vehicle design, product pricing, operating costs associated with capacity investment and design decisions, and the value created by the new products. The application of hybrid technology in the medium truck market illustrates the impact of dual-use decision-making on the commercial enterprise and satisfaction of military performance targets.

  • 11. Corl, Michael J.
    et al.
    Parsons, Michael G.
    Kokkolaras, Michael
    Methodology for the optimization of commonality in multiple ship classes2007Ingår i: Transactions - Society of Naval Architects and Marine Engineers, ISSN 0081-1661, Vol. 115, s. 68-93Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A methodology is presented for the optimization of the use of commonality in multiple classes of ships using mission effectiveness, cost and fleet savings models to evaluate design alternatives. A multicriterion evolutionary algorithm is used to produce the discrete Pareto surface for ships' mission/cost and fleet savings. The methodology is demonstrated and tested using the missions for the U.S. Coast Guard Deepwater High and Medium Endurance Fleets.

  • 12.
    Drignei, Dorin
    et al.
    Oakland University.
    Mourelatos, Zissimos
    Kokkolaras, Michael
    Li, Jing
    Oakland University.
    Koscik, Grzegorz
    Oakland University.
    A Variable-Size Local Domain Approach to Computer Model Validation in Design Optimization2011Ingår i: SAE International Journal of Materials & Manufacturing, ISSN 1946-3979, E-ISSN 1946-3987, Vol. 4, nr 1, s. 421-429Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A common approach to the validation of simulation models focuses on validation throughout the entire design space. A more recent methodology validates designs as they are generated during a simulation-based optimization process. The latter method relies on validating the simulation model in a sequence of local domains. To improve its computational efficiency, this paper proposes an iterative process, where the size and shape of local domains at the current step are determined from a parametric bootstrap methodology involving maximum likelihood estimators of unknown model parameters from the previous step. Validation is carried out in the local domain at each step. The iterative process continues until the local domain does not change from iteration to iteration during the optimization process ensuring that a converged design optimum has been obtained. The proposed methodology is illustrated using a thermal, one-dimensional, linear heat conduction problem in a solid slab with heat flux boundary conditions

  • 13.
    Etman, L.F.P.
    et al.
    Eindhoven University of Technology.
    Hofkamp, A.T.
    Eindhoven University of Technology.
    Rooda, J.E.
    Eindhoven University of Technology.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    Coordination specification for distributed optimal system design using the chi language2002Ingår i: A collection of technical papers: 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization : Atlanta, Georgia, 4 - 6 September 2002, Reston, Va.: American Institute of Aeronautics and Astronautics, AIAA , 2002Konferensbidrag (Refereegranskat)
    Abstract [en]

    Coordination plays a key role in solving decomposed optimal system design problems. Several coordination strategies have been proposed in the multidisciplinary optimization (MDO) literature. They are usually presented as a sequence of statements: the parallel nature of the multidisciplinary subproblems is often either not addressed or only briefly mentioned. However, a more formal description of the concurrency in the coordination is essential, in particular for large and non-hierarchic coordination architectures. This paper proposes to use concepts from communicating sequential processes (CSPs) developed in concurrency theory. CSPs allow the description of the MDO coordination as a number of parallel processes that operate independently and communicate with each other synchronously over pre-defined channels. For this purpose, we introduce elements of the language chi, a CSP-based language that contains data types such as reals, arrays, lists and tuples. The accompanying software tool set that enables the execution of a chi specification has been extended with a Python interface so that function calls to external software can be carried out. Through this interface, chi has been coupled with Matlab to run coordination specifications of distributed optimal system design problems on single or multiple parallel computers. An optimal design example is used to illustrate this. It is concluded that the use of a CSP-based language such as chi for coordinating the solution of MDO problems is quite promising

  • 14.
    Etman, L.F.P.
    et al.
    Department of Mechanical Engineering, Eindhoven University of Technology.
    Kokkolaras, Michael
    Hofkamp, A.T.
    Department of Mechanical Engineering, Eindhoven University of Technology.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Rooda, J.E.
    Department of Mechanical Engineering, Eindhoven University of Technology.
    Coordination specification in distributed optimal design of multilevel systems using the χ language2005Ingår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 29, nr 3, s. 198-212Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Coordination plays a key role in solving decomposed optimal design problems. Several coordination strategies have been proposed in the multidisciplinary optimization (MDO) literature. They are usually presented as a sequence of statements. However, a precise description of the concurrency in the coordination is needed for large multilevel or non-hierarchic coordination architectures. This article proposes the use of communicating sequential processes (CSP) concepts from concurrency theory for specifying and implementing coordination strategies in distributed multilevel optimization rigorously. CSP enables the description of the coordination as a number of parallel processes that operate independently and communicate synchronously. For this purpose, we introduce elements of the language χ, a CSP-based language that contains advanced data modeling constructs. The associated software toolkit allows execution of the specified coordination. Coordination specification using χ is demonstrated for analytical target cascading (ATC), a methodology for design optimization of hierarchically decomposed multilevel systems. It is shown that the ATC coordination can be compactly specified for various coordination schemes. This illustrates the advantage of using a high-level concurrent language, such as χ, for specifying the coordination of distributed optimal design problems. Moreover, the χ software toolkit is useful in implementing alternative schemes rapidly, thus enabling the comparison of different MDO methods.

  • 15.
    Etman, L.F.P.
    et al.
    Eindhoven University of Technology.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    Hofkamp, A.T.
    Eindhoven University of Technology.
    Rooda, J.E.
    Eindhoven University of Technology.
    Coordination specification of the analytical target cascading process using the Chi language2002Ingår i: A collection of technical papers: 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization : Atlanta, Georgia, 4 - 6 September 2002, Reston, Va.: American Institute of Aeronautics and Astronautics, AIAA , 2002Konferensbidrag (Refereegranskat)
  • 16.
    Fellini, R.
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Michelena, N.
    Department of Mechanical Engineering, University of Michigan.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Perez-Duarte, A.
    Department of Mechanical Engineering, University of Michigan.
    Saitou, K.
    Department of Mechanical Engineering, University of Michigan.
    Fenyes, P.
    General Motors R and D Center, Vehicle Development Research Lab.
    A sensitivity-based commonality strategy for family products of mild variation, with application to automotive body structures2004Ingår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 27, nr 1-2, s. 89-96Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Identification of the product platform is a key step in designing a family of products. This article presents a methodology for selecting the product platform by using information obtained from the individual optimization of the product variants. Under the assumption that the product variety requires only mild design changes, a performance deviation vector is derived by taking into consideration individual optimal designs and sensitivities of functional requirements. Commonality decisions are based on values of the performance deviation vector, and the product family is designed optimally with respect to the chosen platform. The proposed methodology is applied to the design of a family of automotive body structures. Variants are defined by changing the functional requirements they need to satisfy and/or the geometry of the associated finite element models.

  • 17.
    Fellini, R.
    et al.
    University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    A math-based methodology for optimal platform selection and design of product families2003Ingår i: Research for practice - innovation in products, processes and organisations: ICED 03, 14th International Conference on Engineering Design ; 19 - 21 August 2003, The Royal Institute of Technology, Stockholm / [ed] Anders Folkeson, Glasgow: Design Research Society, 2003Konferensbidrag (Refereegranskat)
  • 18.
    Fellini, Ryan
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kim, Hyung Min
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Michelena, Nestor
    Department of Mechanical Engineering, University of Michigan.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Target Cascading for Design of Product Families2001Ingår i: Extented abstracts of the fourth world congress of structural and multidisciplinary optimization, June 4-8, 2001, Dalian, China: WCSMO-4, Dalian: Dalian University of Technology Press, 2001Konferensbidrag (Refereegranskat)
  • 19.
    Fellini, Ryan
    et al.
    University of Michigan.
    Kokkolaras, Michael
    Michelena, Nestor
    University of Michigan.
    Papalambros, Panos Y.
    University of Michigan.
    Saitou, Kazuhiro
    University of Michigan.
    Perez-Duarte, Alexis
    University of Michigan.
    Fenves, Peter A.
    University of Michigan.
    A sensitivity-based commonality strategy for family products of mild variation, with application to automotive body structures2002Ingår i: A collection of technical papers: 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization : Atlanta, Georgia, 4 - 6 September 2002, Reston, Va.: American Institute of Aeronautics and Astronautics, AIAA , 2002Konferensbidrag (Refereegranskat)
    Abstract [en]

    Identification of the product platform is n key step in designing a family of products. This article presents a methodology for selecting the product platform using information obtained from the individual optimization of the product variants. Under the assumption that the product variety requires only mild design changes, the authors derive a sharing penalty vector (SPV) by taking into consideration individual optimal designs and sensitivities of functional requirements. Commonality decisions are based on SPY values and the product family is designed optimally with respect to the chosen platform. An automotive body structure problem is used to demonstrate the proposed methodology. Variants are defined by changing the functional requirements they need to satisfy and/or the geometry of the associated finite element models

  • 20.
    Fellini, Ryan
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Commonality decisions in product family design2006Ingår i: Product Platform and Product Family Design: Methods and Applications, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2006, s. 157-185Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Product variants with similar architecture but different functional requirements may have common parts or elements. We define a product family to be a set of such products, and refer to the set of common elements as the product platform. Product platforms enable efficient derivation of product variants by keeping development costs and time-cycles low. In many cases, however, the individual product requirements are conflicting when designing a product family. The designer must balance the tradeoff between maximizing commonality and minimizing individual product performance deviations. The design challenge is to select the product platform that will generate family designs with minimum deviation from individual optima

  • 21.
    Fellini, Ryan
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Efficient product portfolio reduction2003Ingår i: Short papers of the Fifth World Congress of Structural and Multidisciplinary Optimization: May 19 - 23, 2003, Lido di Jesolo, Italy, Milano: Schönenfeld & Ziegler , 2003Konferensbidrag (Refereegranskat)
  • 22.
    Fellini, Ryan
    et al.
    University of Michigan, Ann Arbor.
    Kokkolaras, Michael
    Papalambros, Panos Y,
    University of Michigan, Ann Arbor.
    Quantitative platform selection in optimal design of product families, with application to automotive engine design2006Ingår i: Journal of engineering design (Print), ISSN 0954-4828, E-ISSN 1466-1837, Vol. 17, nr 5, s. 429-446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Product variants with similar architecture but different functional requirements may have common parts. We define a product family to be a set of such products, and refer to the set of common parts as the product platform. Product platforms enable rapid adjustment to changing market needs while keeping development costs and time-cycles low. In many cases, however, the individual product requirements are conflicting when designing a product family. The designer must balance the tradeoff between maximizing commonality and minimizing individual product performance deviations. The design challenge is to select the product platform that will generate family designs with minimum deviation from individual optima. We propose a methodology that combines two previous approaches developed for making commonality decisions. In the first approach optimal values and sensitivity information from the individually optimized variants are used to indicate components that are probable candidates for sharing. In the second approach a relaxed combinatorial problem is formulated to maximize sharing among variants subject to bounds on performance reduction for the individually optimized values. In the combined methodology the first approach is used to identify an initial set of shared components and define the candidate platform to be considered by the second approach. The computational load is reduced significantly and the platform-selection problem is solved in a more robust manner. The proposed methodology is demonstrated on the design of an automotive engine family.

  • 23.
    fellini, Ryan
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Perez-Duarte, Alexis
    Department of Mechanical Engineering, University of Michigan.
    Platform selection under performance bounds in optimal design of product families2005Ingår i: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 127, nr 4, s. 524-535Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Designing a family of product variants that share some components usually requires a compromise in performance relative to the individually optimized variants due to the commonality constraints. Choosing components for sharing may depend on what performance losses can be tolerated. In this article an optimal design problem is formulated to choose product components to be shared without exceeding user-specified bounds on performance. This enables the designer to control tradeoffs and obtain optimal product family designs for maximizing commonality at different levels of acceptable performance. A family of automotive body side frames is used to demonstrate the approach.

  • 24.
    Fellini, Ryan
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Perez-Duarte, Alexis
    Department of Mechanical Engineering, University of Michigan.
    Platform selection under performance loss constraints in optimal design of product families2002Ingår i: Proceedings of the 2002 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference, New York: American Society of Mechanical Engineers , 2002, Vol. 2 : 28th Design Automation Conference, s. 613-621Konferensbidrag (Refereegranskat)
    Abstract [en]

    Designing a family of product variants that share some components usually entails a performance loss relative to the individually optimized variants due to the commonality constraints. Choosing components for sharing may depend on what performance losses can be tolerated. This article presents a methodology for making commonality decisions while controlling individual performance losses. Previous work focused on evaluating individual performance losses due to pre-specified sharing. Trade-offs were identified for different platforms (i.e., the sets of components shared among products) by means of Pareto sets. In the present work an optimal design problem is formulated to choose product components to be shared without exceeding a user-specified performance loss tolerance. This enables the designer to control trade-offs and obtain optimal product family designs for different levels of performance losses in an attempt to maximize commonality. A family of automotive side frames is used to demonstrate the approach

  • 25.
    Filipi, Z.
    et al.
    Automotive Research Center, University of Michigan.
    Louca, L.
    Automotive Research Center, University of Michigan.
    Daran, B.
    Automotive Research Center, University of Michigan.
    Lin, C-C
    Automotive Research Center, University of Michigan.
    Yildir, U.
    Automotive Research Center, University of Michigan.
    Wu, B.
    Automotive Research Center, University of Michigan.
    Kokkolaras, Michael
    Assanis, D.
    Automotive Research Center, University of Michigan.
    Peng, H.
    Automotive Research Center, University of Michigan.
    Papalambros, Panos Y.
    Automotive Research Center, University of Michigan.
    Stein, J.
    Automotive Research Center, University of Michigan.
    Szkubiel, D.
    National Automotive Center, US Army.
    Chapp, R.
    National Automotive Center, US Army.
    Combined optimisation of design and power management of the hydraulic hybrid propulsion system for the 6 × 6 medium truck2004Ingår i: International Journal of Vehicle Design. Heavy Vehicle Design, ISSN 1744-232X, E-ISSN 1741-5152, Vol. 11, nr 3-4, s. 372-402Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hybrid propulsion systems are one of the critical technologies on the roadmap to future ultra-efficient trucks. While there is a significant body of work related to hybrid passenger cars and light commercial trucks, there are many open issues related to hybridisation of heavier trucks intended for both on- and off-road use. This work addresses those questions through a systematic analysis of the proposed parallel hydraulic hybrid powertrain for the Family of Medium Tactical Vehicles (FMTV). A representative duty cycle for the FMTV is generated based on information about the typical vehicle mission. A methodology for sequential optimisation of hybrid propulsion and power management systems is applied to a hydraulic hybrid configuration with posttransmission motor location, This analysis is critical in evaluating the fuel economy and mobility potential of the hybrid propulsion system, as well as enhancing our understanding of the phenomena leading to predicted fuel economy values.

  • 26.
    Gunawan, Subroto
    et al.
    University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    Mourelatos, Zissimos P.
    Oakland University.
    Design Optimization and Reliability Estimation with Incomplete Uncertainty2006Ingår i: 2006 SAE world congress: Detroit, Michigan, April 3 - 6, 2006 ; [papers], Warrendale, Pa.: Society of Automotive Engineers, Incorporated , 2006Konferensbidrag (Refereegranskat)
    Abstract [en]

    Existing methods for design optimization under uncertainty assume that a high level of information is available, typically in the form of data. In reality, however, insufficient data prevents correct inference of probability distributions, membership functions, or interval ranges. In this article we use an engine design example to show that optimal design decisions and reliability estimations depend strongly on uncertainty characterization. We contrast the reliability-based optimal designs to the ones obtained using worst-case optimization, and ask the question of how to obtain non-conservative designs with incomplete uncertainty information. We propose an answer to this question through the use of Bayesian statistics. We estimate the truck's engine reliability based only on available samples, and demonstrate that the accuracy of our estimates increases as more samples become available. Finally, we use this information-based reliability assessment to optimize the engine while maximizing the confidence that the design will meet or exceed a pre-specified reliability target.

  • 27.
    Han, Jeongwoo
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Optimal design of hybrid fuel cell vehicles2006Ingår i: Proceedings of the 4th International Conference on Fuel Cell Science, Engineering, and Technology - 2006: presented at ... June 19 - 21, 2006, Irvine, California, USA, New York: American Society of Mechanical Engineers , 2006, s. 273-282Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fuel cells are being considered increasingly as a viable alternative energy source for automobiles because of their clean and efficient power generation. Numerous technological concepts have been developed and compared in terms of safety, robust operation, fuel economy, and vehicle performance. However, several issues still exist and must be addressed to improve the viability of this emerging technology. Despite the relatively large number of models and prototypes, a model-based vehicle design capability with sufficient fidelity and efficiency is not yet available in the literature. In this article we present an analysis and design optimization model for fuel cell vehicles that can be applied to both hybrid and non-hybrid vehicles by integrating a fuel cell vehicle simulator with a physics-based fuel cell model. The integration is achieved via quasi-steady fuel cell performance maps, and provides the ability to modify the characteristics of fuel cell systems with sufficient accuracy (less than 5% error) and efficiency (98% computational time reduction on average). Thus, a vehicle can be optimized subject to constraints that include various performance metrics and design specifications so that the overall efficiency of the hybrid fuel cell vehicle can be improved by 14% without violating any constraints. The obtained optimal fuel cell system is also compared to other, not vehicle-related, fuel cell systems optimized for maximum power density or maximum efficiency. A tradeoff between power density and efficiency can be observed depending on the size of compressors. Typically, a larger compressor results in higher fuel cell power density at the cost of fuel cell efficiency because it operates in a wider current region. When optimizing the fuel cell system for maximum power density, we observe that the optimal compressor operates efficiently. When optimizing the fuel cell system to be used as a power source in a vehicle, the optimal compressor is smaller and less efficient than the one of the fuel cell system optimized for maximum power density. In spite of this compressor inefficiency, the fuel cell system is 9% more efficient on average. In addition, vehicle performance can be improved significantly because the fuel cell system is designed both for maximum power density and efficiency. For a more comprehensive understanding of the overall design tradeoffs, several constraints dealing with cost, weight, and packaging issues must be considered

  • 28.
    Han, Jeongwoo
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Optimal Design of Hybrid Fuel Cell Vehicles2008Ingår i: Journal of Fuel Cell Science and Technology, ISSN 1550-624X, E-ISSN 1551-6989, Vol. 5, nr 4Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Automotive use of fuel cells has received increased attention due to clean and efficient power generation. Successful vehicular applications require careful balance of design and control trade-offs. This article presents a model-based vehicle design capability with sufficient fidelity and efficiency to perform design and power management optimization using quasisteady fuel cell performance maps. Optimized fuel cell systems demonstrate a trade-off between power density and efficiency depending on compressor size. Vehicle performance can be improved significantly when the fuel cell system is designed to balance this trade-off

  • 29.
    Heinkenschloss, Matthias
    et al.
    Rice University, Houston.
    Hribar, Mary B.
    Rice University, Houston.
    Kokkolaras, Michael
    Acceleration of multidisciplinary analysis solvers by inexact subsystem simulations1998Ingår i: 7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization: September 2 - 4, 1998, St. Louis, MO, Reston, Va.: American Institute of Aeronautics and Astronautics, AIAA , 1998Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper is concerned with the numerical solution of systems of blocked nonlinear equations arising in the solution of multidisciplinary analysis (MDA) problems. We consider the case where individual discipline solvers/simulators are given and are iterative methods. Thus, an MDA solver consists of an outer iteration for the solution of the system of blocked nonlinear equations and of inner iterations in the discipline simulators. We show how the control of the truncation of the inner iterations can be effectively used to accelerate the overall iteration. The key is the interpretation of the outer iteration with inexact inner iteration as an iteration of a related system with the same solution as the MDA problem.

  • 30.
    Hoffenson, S.
    et al.
    University of Michigan.
    Arepally, S.
    University of Michigan.
    Kokkolaras, Michael
    Papalambros, P.Y.
    University of Michigan.
    Quantification of the design relationship between ground vehicle weight and occupant safety under blast loading2013Ingår i: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 61, nr 1/2/3/4, s. 204-218Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Military ground vehicle design must consider the threat posed by underbody blasts to new vehicles and their occupants, while also accounting for weight reduction goals for improving fuel economy and mobility. A two-stage process is presented to model the blast event, using LS-DYNA for simulating vehicle response and MADYMO for the occupant's response. Issues including computational expense, objective function formulation and multi-objective seating system design optimisation are addressed in detail, and three different blastworthiness optimisation formulations are presented and evaluated

  • 31.
    Hoffenson, Steven
    et al.
    University of Michigan.
    Arepally, Sudhakar
    TARDEC.
    Kokkolaras, Michael
    Papalambros, Panos Y.
    University of Michigan.
    Ground Vehicle Safety Optimization Considering Blastworthiness and the Risks of High Weight and Fuel Consumption2011Konferensbidrag (Refereegranskat)
  • 32.
    Hoffenson, Steven
    et al.
    University of Michigan.
    Papalambros, Panos Y.
    University of Michigan.
    Kokkolaras, Michael
    Arepally, Sudhakar
    U.S. Army Tank Automotive Research Development and Engineering Center, Warren, MI.
    Weight and Blastworthiness Design Considerations for Military Ground Vehicle Safety Optimization2011Konferensbidrag (Refereegranskat)
  • 33.
    Hoffenson, Steven
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Papalambros, Pahos Y.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Reed, Matthew
    University of Michigan, Transportation Research Institute, Ann Arbor.
    An Optimization Approach to Occupant Safety and Fuel Economy in Vehicle Design2009Ingår i: WCSMO-8: 8th World Congress on Structural and Multidisciplinary Optimization, 2009Konferensbidrag (Övrigt vetenskapligt)
  • 34.
    Hu, Jingwen
    et al.
    University of Michigan, Transportation Research Institute, Ann Arbor.
    Klinich, Kathleen D.
    University of Michigan, Transportation Research Institute, Ann Arbor.
    Reed, Matthew P.
    University of Michigan, Transportation Research Institute, Ann Arbor.
    Kokkolaras, Michael
    Rupp, Jonathan D.
    University of Michigan, Transportation Research Institute, Ann Arbor.
    Development and validation of a modified hybrid-III six-year-old dummy model for simulating submarining in motor-vehicle crashes2012Ingår i: Medical Engineering and Physics, ISSN 1350-4533, E-ISSN 1873-4030, Vol. 34, nr 5, s. 541-551Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In motor-vehicle crashes, young school-aged children restrained by vehicle seat belt systems often suffer from abdominal injuries due to submarining. However, the current anthropomorphic test device, so-called “crash dummy”, is not adequate for proper simulation of submarining. In this study, a modified Hybrid-III six-year-old dummy model capable of simulating and predicting submarining was developed using MADYMO (TNO Automotive Safety Solutions). The model incorporated improved pelvis and abdomen geometry and properties previously tested in a modified physical dummy. The model was calibrated and validated against four sled tests under two test conditions with and without submarining using a multi-objective optimization method. A sensitivity analysis using this validated child dummy model showed that dummy knee excursion, torso rotation angle, and the difference between head and knee excursions were good predictors for submarining status. It was also shown that restraint system design variables, such as lap belt angle, D-ring height, and seat coefficient of friction (COF), may have opposite effects on head and abdomen injury risks; therefore child dummies and dummy models capable of simulating submarining are crucial for future restraint system design optimization for young school-aged children

  • 35.
    Isaksson, Ola
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Larsson, Tobias
    Kokkolaras, Michael
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Bertoni, Marco
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Simulation driven design for product-service systems2012Ingår i: The Philosopher's Stone for Sustainability: Proceedings of the 4th CIRP International Conference on Industrial Product-Service Systems, Tokyo, Japan, November 8th-9th, 2012 / [ed] Yoshiki Shimomura; Koji Kimita, Berlin Heidelberg: Encyclopedia of Global Archaeology/Springer Verlag, 2012, s. 465-470Konferensbidrag (Refereegranskat)
    Abstract [en]

    Total Offers, Functional Products, and Integrated Product Service Engineering reflect a shift toward service offers from manufacturing industry captured within the term Product-Service Systems (PSS). Manufacturing companies have traditionally focused design and development activities on realizing technical and engineered aspects of physical artifacts, while PSS include deeper understanding of customers’ expectation, needs and perceived value, hence calling for modelling of additional aspects. The change in early design processes and the effects on virtual modelling of product properties are discussed in this paper through aerospace industry examples to clarify ‘parameters of change’, giving suggestions for a simulation driven design (SDD) approach.

  • 36.
    Jr., A.J. Meade
    et al.
    William Marsh Rice University, Houston.
    Kokkolaras, Michael
    Enhancement of a viscous-inviscid-interaction airfoil analysis code using the parallel direct search algorithm1997Ingår i: Mathematical and computer modelling, ISSN 0895-7177, E-ISSN 1872-9479, Vol. 25, nr 6, s. 85-96Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The coupling mechanism for an existing viscous-inviscid-interaction (VII) code, developed for the analysis of two-dimensional, turbulent, attached flow around airfoils, is enhanced using the parallel direct search (PDS) optimization algorithm. It is demonstrated that this parallel processing implemented optimization scheme leads to faster convergence of the VII code, and therefore, requires less computational time when the number of optimization (or design) variables is low, and a moderate number of processors are available. As the number of design variables increases, more processors are required to maintain this advantage. Results are presented for the NACA-0012 and the RAE-2822 airfoils. The quality of the results obtained is satisfactory and confirms that the enhanced VII code can be an acceptable alternative to reduced Navier-Stokes solvers as an airfoil analysis tool.

  • 37.
    Jr., A.J. Meade
    et al.
    Department of Mechanical Engineering and Materials Science, William Marsh Rice University, Houston.
    Kokkolaras, Michael
    Zeldin, B.A.
    Department of Mechanical Engineering and Materials Science, William Marsh Rice University, Houston.
    Sequential function approximation for the solution of differential equations1997Ingår i: Communications in Numerical Methods in Engineering, ISSN 1069-8299, E-ISSN 1099-0887, Vol. 13, nr 12, s. 977-986Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A computational method for the solution of differential equations is proposed. With this method an accurate approximation is built by incremental additions of optimal local basis functions. The parallel direct search software package (PDS), that supports parallel objective function evaluations, is used to solve the associated optimization problem efficiently. The advantage of the method is that, although it resembles adaptive methods in computational mechanics, an a priori grid is not necessary. Moreover, the traditional matrix construction and evaluations are avoided. Computational cost is reduced while efficiency is enhanced by the low-dimensional parallel-executed optimization and parallel function evaluations. In addition, the method should be applicable to a broad class of interpolation functions. Results and global convergence rates obtained for one- and two-dimensional boundary value problems are satisfactorily compared to those obtained by the conventional Galerkin finite element method

  • 38.
    Jr., Andrew J. Meade
    et al.
    Department of Mechanical Engineering, Rice University, Houston.
    Kokkolaras, Michael
    Zeldin, Boris
    Department of Mechanical Engineering, Rice University, Houston.
    Adaptive solution of differential equations for the regularization of artificial neural networks1998Ingår i: Intelligent systems for humans in a cyberworld: 1998 IEEE International Conference on Systems, Man, and Cybernetics, Hyatt Regency La Jolla, San Diego, California, USA, October 11 - 14, 1998 / [ed] Meng-Chu Zhou, Piscataway, NJ: IEEE Communications Society, 1998, Vol. 4, s. 3130-3135Konferensbidrag (Refereegranskat)
    Abstract [en]

    The authors propose using artificial neural networks to model the solution of the two-dimensional Euler equation which models inviscid and compressible fluid flow. The code thus created should not only have the same accuracy as a more conventional computer code, but should still retain the ability of an ANN to modify itself when exposed to experimental data, thus yielding software that could be specialized with experimental results. To accomplish these objectives, the method of optimal incremental function approximation has been developed for the adaptive solution of differential equations using ANN architecture. Two major attractive features of this approach are that: (1) the developed method is flexible enough to use any of the popular transfer functions and (2) the developed method requires minimal user interaction. The latter is especially advantageous when dealing with complicated physical or computational domains. Numerical results are presented and compared to conventional methods. The accuracy is considered satisfactory

  • 39.
    Kim, H.M.
    et al.
    Department of Mechanical Engineering, University of Michigan.
    Kokkolaras, Michael
    Louca, L.S.
    Department of Mechanical Engineering, University of Michigan.
    Delagrammatikas, G.J.
    Department of Mechanical Engineering, University of Michigan.
    Michelena, N.F.
    Department of Mechanical Engineering, University of Michigan.
    Filipi, Z.S.
    Department of Mechanical Engineering, University of Michigan.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Stein, J.L.
    Department of Mechanical Engineering, University of Michigan.
    Assanis, D.N.
    Department of Mechanical Engineering, University of Michigan.
    Target cascading in vehicle redesign: A class VI truck study2002Ingår i: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 29, nr 3, s. 199-225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The analytical target cascading process is applied to the redesign of a U.S. class VI truck. Necessary simulation and analysis models for predicting vehicle dynamics, powertrain, and suspension behaviour are developed. Vehicle design targets that include improved fuel economy, ride quality, driveability, and performance metrics are translated into system design specifications, and a consistent final design is obtained. Trade-offs between conflicting targets are identified. The study illustrates how the analytical target cascading process can reduce vehicle design cycle time while ensuring physical prototype matching, and how costly design iterations late in the development process can be avoided

  • 40. Kokkolaras, Michael
    Hierarchical Multilevel Optimization for Reliability Target Allocation in Probabilistic Design of Decomposed Systems2007Ingår i: ICIAM 07: 6th International Congress on Industrial and Applied Mathematics, Zürich, Switzerland, 16-20 July, 2007 ; invited lectures, Zürich: European Mathematical Society Publishing House, 2007Konferensbidrag (Refereegranskat)
  • 41. Kokkolaras, Michael
    Reliability allocation in probabilistic design optimization of decomposed systems using analytical target cascading2008Ingår i: 12th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference: MAO ; 10 - 12 September 2008, Victoria, British Columbia, Canada ; [papers], Reston, Va: American Institute of Aeronautics and Astronautics, AIAA , 2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Analytical target cascading (ATC) is a methodology for translating system design targets to design specifications for the elements comprising a decomposed engineering system. In previous work we extended the ATC formulation to reliability-based design optimization (RBDO) problems, where the bounds of the probabilistic design constraints for each subproblem were assigned arbitrarily and held fixed during the ATC process. In this work, we extend the probabilistic ATC formulation to include reliability targets in the cascaded quantities. We employ a series-system formulation to solve the RBDO problem associated with each element of the ATC hierarchy and to compute its reliability. Thus, we quantify the optimality-reliability tradeoffs for each element of the decomposed system, which allows us to determine the probabilistic constraint bounds required to satisfy the overall system reliability target. In this manner we cascade the latter to element reliability specifications

  • 42. Kokkolaras, Michael
    et al.
    Audet, Charles
    Departement de Mathematiques et de Genie Industriel, Ecole Polytechnique de Montreal.
    Jr., J.E. Dennis
    Department of Computational and Applied Mathematics, Rice University, Houston.
    Mixed Variable Optimization of the Number and Composition of Heat Intercepts in a Thermal Insulation System2001Ingår i: Optimization and Engineering, ISSN 1389-4420, E-ISSN 1573-2924, Vol. 2, nr 1, s. 42519-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the literature, thermal insulation systems with a fixed number of heat intercepts have been optimized with respect to intercept locations and temperatures. The number of intercepts and the types of insulators that surround them were chosen by parametric studies. This was because the optimization methods used could not treat such categorical variables. Discrete optimization variables are categorical if the objective function or the constraints can not be evaluated unless the variables take one of a prescribed enumerable set of values. The key issue is that categorical variables can not be treated as ordinary discrete variables are treated by relaxing them to continuous variables with a side constraint that they be discrete at the solution. A new mixed variable programming (MVP) algorithm makes it possible to optimize directly with respect to mixtures of discrete, continuous, and categorical decision variables. The result of applying MVP is shown here to give a 65% reduction in the objective function over the previously published result for a thermal insulation model from the engineering literature. This reduction is largely because MVP optimizes simultaneously with respect to the number of heat intercepts and the choices from a list of insulator types as well as intercept locations and temperatures. The main purpose of this paper is to show that the mixed variable optimization algorithm can be applied effectively to a broad class of optimization problems in engineering that could not be easily solved with earlier methods

  • 43. Kokkolaras, Michael
    et al.
    Fellini, R.
    Department of Mechanical Engineering, University of Michigan.
    Kim, H.M.
    Department of Mechanical Engineering, University of Michigan.
    Michelena, N.F.
    Department of Mechanical Engineering, University of Michigan.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Extension of the target cascading formulation to the design of product families2002Ingår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 24, nr 4, s. 293-301Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The target cascading methodology for optimal product development is extended to product families with predefined platforms. The single-product formulation is modified to accommodate the presence of shared systems, subsystems, and/or components and locally introduced targets. Hierarchical optimization problems associated with each product variant are combined to formulate the product family multicriteria design problem, and common subproblems are identified based on the shared elements (i.e. the platform). The solution of the overall design problem is coordinated so that the shared elements are consistent with the performance and behaviour of the product variants. A simple automotive design example is used to demonstrate the proposed methodology.

  • 44. Kokkolaras, Michael
    et al.
    Fellini, Ryan
    Department of Mechanical Engineering, University of Michigan.
    Kim, Harrison M.
    Department of General Engineering, University of Illinois Urbana-Champaign.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Analytical target cascading in product family design2006Ingår i: Product Platform and Product Family Design: Methods and Applications, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2006, s. 225-240Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Most products are neither designed nor manufactured as one piece. They are decomposed into parts that are developed individually before they are assembled to form the final product. Typically, this partitioning-based development process matches the hierarchical structure of the productoffering organization. Design tasks are assigned to divisions, departments, and teams according to expertise. An example from the automotive industry is depicted in Figure 11-1. Obviously, this decomposition is not complete and serves only as an illustration of the decomposition paradigm.

  • 45. Kokkolaras, Michael
    et al.
    Hulbert, G.
    University of Michigan.
    Papalambros, P.
    University of Michigan.
    Mourelatos, Z.
    University of Michigan.
    Yang, R.-J.
    University of Michigan.
    Brudnak, M.
    University of Michigan.
    Gorsich, D.
    University of Michigan.
    Towards a comprehensive framework for simulation-based vehicle systems design validation2013Ingår i: International Journal of Vehicle Design, ISSN 0143-3369, E-ISSN 1741-5314, Vol. 61, nr .1/2/3/4, s. 233-248Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present an overview of our most recent and ongoing research efforts to develop a comprehensive framework for simulation-based design validation of vehicle systems. Specifically, we present the three major building blocks of our framework: (1) the introduction of an appropriate validation metric for dealing with the multivariate functional data that are the output of dynamic vehicle systems; (2) the robust implementation of a Bayesian interval-based hypothesis testing technique for quantifying the confidence in simulation models used for design under uncertainty; (3) the development of a sequential design optimisation and calibration-based validation methodology that addresses the inadequacy of current validation practices in simulation-based design optimisation. We present a simple yet illustrative example and discuss the techniques being developed currently that will complete the proposed framework

  • 46. Kokkolaras, Michael
    et al.
    Jr., Andrew J. Meade
    Department of Mechanical Engineering and Materials Science, Rice University.
    Zeldin, Boris
    Software Engineer, Vignette Corporation.
    Concurrent Implementation of the Optimal Incremental Approximation Method for the Adaptive and Meshless Solution of Differential Equations2003Ingår i: Optimization and Engineering, ISSN 1389-4420, E-ISSN 1573-2924, Vol. 4, nr 4, s. 271-289Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optimal incremental function approximation method is implemented for the adaptive and meshless solution of differential equations. The basis functions and associated coefficients of a series expansion representing the solution are selected optimally at each step of the algorithm according to appropriate error minimization criteria. Thus, the solution is built incrementally. In this manner, the computational technique is adaptive in nature, although a grid is neither built nor adapted in the traditional sense using a posteriori error estimates. Since the basis functions are associated with the nodes only, the method can be viewed as a meshless method. Variational principles are utilized for the definition of the objective function to be extremized in the associated optimization problems. Complicated data structures, expensive remeshing algorithms, and systems solvers are avoided. Computational efficiency is increased by using low-order local basis functions and the parallel direct search (PDS) optimization algorithm. Numerical results are reported for both a linear and a nonlinear problem associated with fluid dynamics. Challenges and opportunities regarding the use of this method are discussed

  • 47. Kokkolaras, Michael
    et al.
    Louca, L.S.
    Department of Mechanical Engineering, University of Michigan.
    Delagrammatikas, G.J.
    Department of Mechanical Engineering, University of Michigan.
    Michelena, N.F.
    Department of Mechanical Engineering, University of Michigan.
    Filipi, Z.S.
    Department of Mechanical Engineering, University of Michigan.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Stein, J.L.
    Department of Mechanical Engineering, University of Michigan.
    Assanis, D.N.
    Department of Mechanical Engineering, University of Michigan.
    Simulation-based optimal design of heavy trucks by model-based decomposition: An extensive analytical target cascading case study2004Ingår i: International Journal of Vehicle Design. Heavy Vehicle Design, ISSN 1744-232X, E-ISSN 1741-5152, Vol. 11, nr 3-4, s. 403-433Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the findings of an extensive case study for the decomposed, simulation-based, optimal design of an advanced technology heavy truck by means of analytical target cascading. The use of a series hybridelectric propulsion system, in-hub motors, and variable height suspensions is considered with the intention of improving both commercial and military design attributes according to a dual-use philosophy. Emphasis is given to fuel economy, ride, and mobility characteristics. The latter are predicted by appropriately developed analytical and simulation models. This article builds on previous work and focuses on recent efforts to refine the applied methodologies and draw final conclusions.

  • 48. Kokkolaras, Michael
    et al.
    Mourelatos, Zissemos P.
    Department of Mechanical Engineering, University of Michigan.
    Papalambros, Panos Y.
    Department of Mechanical Engineering, University of Michigan.
    Impact of uncertainty quantification on design: an engine optimisation case study2006Ingår i: International Journal of Reliability and Safety, ISSN 1479-389X, E-ISSN 1479-3903, Vol. 1, nr 1-2, s. 225-237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The method for solving design optimisation problems when some or all design variables and/or parameters are not deterministic depends on how we quantify uncertainty. Probabilistic design methods can be employed when sufficient information is available. In reality, however, we often do not have enough knowledge and/or data to conduct statistical inference. The amount of available information about the uncertain quantities may be limited to ranges of values. Possibility theory may then be employed to reformulate and solve the optimal design problem. In this paper, we use both probability and possibility theories to determine optimal values of engine characteristics for a hydraulic-hybrid powertrain of a medium-sized truck while accounting for the most significant modelling uncertainties. A worst-case optimisation using interval analysis is considered as a special case of possibilistic design. We contrast the two sets of results, draw some conclusions and discuss features of the two approaches.

  • 49. Kokkolaras, Michael
    et al.
    Mourelatos, Zissimos
    Oakland University, Rochester.
    Louca, Loucas
    University of Cyprus, Nicosia.
    Filipi, Zoran
    University of Michigan.
    Delagrammatikas, George
    California Polytechnic State University, San Luis Obispo.
    Stefanopoulou, Anna
    University of Michigan.
    Papalambros, Panos Y.
    University of Michigan.
    Assanis, Dennis
    University of Michigan.
    Design Under Uncertainty and Assessment of Performance Reliability of a Dual-Use Medium Truck with Hydraulic-Hybrid Powertrain and Fuel Cell Auxiliary Power Unit2005Ingår i: 2005 SAE world congress: Detroit, Michigan, April 11 - 14, 2005, Warrendale, Pa: Society of Automotive Engineers, Incorporated , 2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    Medium trucks constitute a large market segment of the commercial transportation sector, and are also used widely for military tactical operations. Recent technological advances in hybrid powertrains and fuel cell auxiliary power units have enabled design alternatives that can improve fuel economy and reduce emissions dramatically. However, deterministic design optimization of these configurations may yield designs that are optimal with respect to performance but raise concerns regarding the reliability of achieving that performance over lifetime. In this article we identify and quantify uncertainties due to modeling approximations or incomplete information. We then model their propagation using Monte Carlo simulation and perform sensitivity analysis to isolate statistically significant uncertainties. Finally, we formulate and solve a series of reliability-based optimization problems and quantify tradeoffs between optimality and reliability. The most relevant design parameters of the diesel engine, fuel cell, driveline and vehicle are considered. The results demonstrate the necessity for addressing uncertainty to make valid assessments and design decisions

  • 50. Kokkolaras, Michael
    et al.
    Mourelatos, Zissimos P.
    Oakland University.
    Papalambros, Panos Y.
    University of Michigan.
    Design optimization of hierarchically decomposed multilevel systems under uncertainty2004Ingår i: Proceedings of the ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference - 2004: presented at 2004 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference, September 28 - October 2, 2004, Salt Lake City, Utah, New York: American Society of Mechanical Engineers , 2004, Vol. 1 : 30th Design Automation Conference, s. 613-625Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a methodology for design optimization of decomposed systems in the presence of uncertainties. We extend the analytical target cascading (ATC) formulation to probabilistic design by treating stochastic quantities as random variables and parameters and posing reliability-based design constraints. We model the propagation of uncertainty throughout the multilevel hierarchy of elements that comprise the decomposed system by using the advanced mean value (AMV) method to generate the required probability distributions of nonlinear responses. We utilize appropriate metamodeling techniques for simulation-based design problems. A simple yet illustrative hierarchical bi-level engine design problem is used to demonstrate the proposed methodology.

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