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Lindgren, L.-E. & Lundbäck, A. (2018). Approaches in computational welding mechanics applied to additive manufacturing: Review and outlook. Comptes rendus. Mecanique
Open this publication in new window or tab >>Approaches in computational welding mechanics applied to additive manufacturing: Review and outlook
2018 (English)In: Comptes rendus. Mecanique, ISSN 1631-0721, E-ISSN 1873-7234Article in journal (Refereed) Epub ahead of print
Abstract [en]

The development of computational welding mechanics (CWM) began more than four decades ago. The approach focuses on the region outside the molten pool and is used to simulate the thermo-metallurgical-mechanical behaviour of welded components. It was applied to additive manufacturing (AM) processes when they were known as weld repair and metal deposition. The interest in the CWM approach applied to AM has increased considerably, and there are new challenges in this context regarding welding. The current state and need for developments from the perspective of the authors are summarised in this study.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-70648 (URN)10.1016/j.crme.2018.08.004 (DOI)
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-08-29
Lindwall, J., Malmelöv, A., Lundbäck, A. & Lindgren, L.-E. (2018). Efficiency and Accuracy in Thermal Simulation of Powder Bed Fusion of Bulk Metallic Glass. JOM: The Member Journal of TMS, 70(8), 1598-1603
Open this publication in new window or tab >>Efficiency and Accuracy in Thermal Simulation of Powder Bed Fusion of Bulk Metallic Glass
2018 (English)In: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 70, no 8, p. 1598-1603Article in journal (Refereed) Published
Abstract [en]

Additive manufacturing by powder bed fusion processes can be utilized to create bulk metallic glass as the process yields considerably high cooling rates. However, there is a risk that reheated material set in layers may become devitrified, i.e., crystallize. Therefore, it is advantageous to simulate the process to fully comprehend it and design it to avoid the aforementioned risk. However, a detailed simulation is computationally demanding. It is necessary to increase the computational speed while maintaining accuracy of the computed temperature field in critical regions. The current study evaluates a few approaches based on temporal reduction to achieve this. It is found that the evaluated approaches save a lot of time and accurately predict the temperature history.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-68768 (URN)10.1007/s11837-018-2919-8 (DOI)000440845900039 ()
Note

Validerad;2018;Nivå 2;2018-08-07 (rokbeg)

Available from: 2018-05-17 Created: 2018-05-17 Last updated: 2018-08-23Bibliographically approved
Fisk, M., Lindgren, L.-E., Datchary, W. & Deshmukh, V. (2018). Modelling of induction hardening in low alloy steels. Finite elements in analysis and design (Print), 144, 61-75
Open this publication in new window or tab >>Modelling of induction hardening in low alloy steels
2018 (English)In: Finite elements in analysis and design (Print), ISSN 0168-874X, E-ISSN 1872-6925, Vol. 144, p. 61-75Article in journal (Refereed) Published
Abstract [en]

Induction hardening is a useful method for improving resistance to surface indentation, fatigue and wear that is favoured in comparison with through hardening, which may lack necessary toughness. The process itself involves fast heating by induction with subsequent quenching, creating a martensitic layer at the surface of the workpiece. In the present work, we demonstrate how to simulate the process of induction hardening using a commercial finite element software package with focuses on validation of the electromagnetic and thermal parts, together with evolution of the microstructure. Experiments have been carried out using fifteen workpieces that have been heated using three different heating rates and five different peak temperatures resulting in different microstructures. It is found that the microstructure and hardening depth is affected by the heating rate and peak temperature. The agreement between the experimental and simulated results is good. Also, it is demonstrated that the critical equilibrium temperatures for phase transformation is important for good agreement between the simulated and experimental hardening depth. The developed simulation technique predicts the hardness and microstructure sufficiently well for design and the development of induction hardening processes.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-67999 (URN)10.1016/j.finel.2018.03.002 (DOI)000431206900006 ()2-s2.0-85044131610 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-03-19 (andbra)

Available from: 2018-03-19 Created: 2018-03-19 Last updated: 2018-07-18Bibliographically approved
Zamani, M., Dini, H., Svoboda, A., Lindgren, L.-E., Seifeddine, S., Andersson, N.-E. & Jarfors, A. E. .. (2017). A dislocation density based constitutive model for as-cast Al-Si alloys: Effect of temperature and microstructure. International Journal of Mechanical Sciences, 121, 164-170
Open this publication in new window or tab >>A dislocation density based constitutive model for as-cast Al-Si alloys: Effect of temperature and microstructure
Show others...
2017 (English)In: International Journal of Mechanical Sciences, ISSN 0020-7403, E-ISSN 1879-2162, Vol. 121, p. 164-170Article in journal (Refereed) Published
Abstract [en]

The flow stress of an as-cast Al-Si based alloy was modeled using a dislocation density based model. The developed dislocation density-based constitutive model describes the flow curve of the alloy with various microstructures at quite wide temperature range. Experimental data in the form of stress-strain curves for different strain rates ranging from 10−4 to 10−1 s−1 and temperatures ranging from ambient temperature up to 400 °C were used for model calibration. In order to model precisely the hardening and recovery process at elevated temperature, the interaction between vacancies and dissolved Si was included. The calibrated temperature dependent parameters for different microstructure were correlated to the metallurgical event of the material and validated. For the first time, a dislocation density based model was successfully developed for Al-Si cast alloys. The findings of this work expanded the knowledge on short strain tensile deformation behaviour of these type of alloys at different temperature, which is a critical element for conducting a reliable microstructural FE-simulation.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-61341 (URN)10.1016/j.ijmecsci.2017.01.003 (DOI)000395216300015 ()2-s2.0-85008703756 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-01-09 (andbra)

Available from: 2017-01-09 Created: 2017-01-09 Last updated: 2018-09-12Bibliographically approved
Azizoğlu, Y., Gärdsback, M., Sjöberg, B. & Lindgren, L.-E. (2017). Finite Element Analysis of cold pilgering using elastic roll dies. Paper presented at International Conference on the Technology of Plasticity, ICTP 2017, Cambridge, United Kingdom, 17-22 September 2017. Procedia Engineering, 207, 2370-2375
Open this publication in new window or tab >>Finite Element Analysis of cold pilgering using elastic roll dies
2017 (English)In: Procedia Engineering, ISSN 1877-7058, E-ISSN 1877-7058, Vol. 207, p. 2370-2375Article in journal (Refereed) Published
Abstract [en]

A finite element model of cold pilgering with elastic roll dies have been developed and used to investigate the influence of roll die deformation on the material flow, contact region, roll separating force and tube dimensions. Full scale experiments were performed to validate the contact surface and tube dimensions. The results show that the influence of roll die flattening is not significant on the contact length. However, elastic deformation of roll die has strong influence on both the wall thickness reduction and roll separating force. Thus it is recommended to consider elasticity of roll dies when forces and tube dimensions are estimated.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
cold pilgering; cold forming; tube forming; roll flattening; contact length; roll separating force; finite element method; tool elasticity; tube dimension
National Category
Applied Mechanics Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-62938 (URN)10.1016/j.proeng.2017.10.1010 (DOI)2-s2.0-85036627374 (Scopus ID)
Conference
International Conference on the Technology of Plasticity, ICTP 2017, Cambridge, United Kingdom, 17-22 September 2017
Note

Konferensartikel i tidskrift

Available from: 2017-04-07 Created: 2017-04-07 Last updated: 2017-12-19Bibliographically approved
Lindgren, L.-E., Qin, H. & Wedberg, D. (2017). Improved and simplified dislocation density based plasticity model for AISI 316 L. Mechanics of materials (Print), 108, 68-76
Open this publication in new window or tab >>Improved and simplified dislocation density based plasticity model for AISI 316 L
2017 (English)In: Mechanics of materials (Print), ISSN 0167-6636, E-ISSN 1872-7743, Vol. 108, p. 68-76Article in journal (Refereed) Published
Abstract [en]

A previously published dislocation density based flow stress model has been refined and made more consistent with underlying physical assumptions. The previous model included many temperature dependent parameters that are taken as constant in the current work. The model has also been simplified with respect to dynamic strain aging. Additional contributions to flow stress from the Hall-Petch effect and solute hardening have now been explicitly included in the model. Furthermore, the dynamic recovery part of the model has been improved.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-62446 (URN)10.1016/j.mechmat.2017.03.007 (DOI)000399859100006 ()2-s2.0-85015320929 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-03-17 (rokbeg)

Available from: 2017-03-13 Created: 2017-03-13 Last updated: 2018-09-13Bibliographically approved
Gyhlesten Back, J. & Lindgren, L.-E. (2017). Influence of prior deformation in austenite on the martensite formation in a low-alloyed carbon steel.
Open this publication in new window or tab >>Influence of prior deformation in austenite on the martensite formation in a low-alloyed carbon steel
2017 (English)In: Article in journal (Refereed) Submitted
Keywords
Steel, Martensite, Phase transformation, Modelling, Thermal strain
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-62367 (URN)
Available from: 2017-03-09 Created: 2017-03-09 Last updated: 2017-11-24
Thipprakmas, S., Joun, M. S. & Lindgren, L.-E. (2017). Modern Engineered Materials and Technologies for Metal Forming Applications. Advances in Materials Science and Engineering, 2017, Article ID 3196509.
Open this publication in new window or tab >>Modern Engineered Materials and Technologies for Metal Forming Applications
2017 (English)In: Advances in Materials Science and Engineering, ISSN 1687-8434, E-ISSN 1687-8442, Vol. 2017, article id 3196509Article in journal, Editorial material (Refereed) Published
Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2017
National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-63097 (URN)10.1155/2017/3196509 (DOI)000405702800001 ()2-s2.0-85017121094 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-08-16 (andbra)

Available from: 2017-04-20 Created: 2017-04-20 Last updated: 2018-07-10Bibliographically approved
Abiri, O., Wedberg, D., Svoboda, A. & Lindgren, L.-E. (2017). Non-Local Modelling of Strain Softening in Machining Simulations. Paper presented at International Conference on Materials, Alloys and Experimental Mechanics (ICMAEM-2017), Narsimha Reddy Engineering College, India, 3–4 July 2017. IOP Conference Series: Materials Science and Engineering, 225, Article ID 012053.
Open this publication in new window or tab >>Non-Local Modelling of Strain Softening in Machining Simulations
2017 (English)In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 225, article id 012053Article in journal (Refereed) Published
Abstract [en]

Non-local damage model for strain softening in a machining simulation is presented in this paper. The coupled damage-plasticity model consists of a physically based dislocation density model and a damage model driven by plastic straining in combination with the stress state. The predicted chip serration is highly consistent with the measurement results. 

Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2017
Keywords
Finite element simulation; Machining; Non-local models; Damage model; Plasticity
National Category
Applied Mechanics Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-65635 (URN)10.1088/1757-899X/225/1/012053 (DOI)000412003600053 ()
Conference
International Conference on Materials, Alloys and Experimental Mechanics (ICMAEM-2017), Narsimha Reddy Engineering College, India, 3–4 July 2017
Funder
VINNOVA
Note

Konferensartikel i tidskrift

Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2017-11-24Bibliographically approved
Abiri, O., Qin, H. & Lindgren, L.-E. (2016). Comparison of Multiresolution Continuum Theory and Nonlocal Dame model for use in Simulation of Manufacutring Processes (ed.). Paper presented at . International Journal for Multiscale Computational Engineering, 14(1), 81-94
Open this publication in new window or tab >>Comparison of Multiresolution Continuum Theory and Nonlocal Dame model for use in Simulation of Manufacutring Processes
2016 (English)In: International Journal for Multiscale Computational Engineering, ISSN 1543-1649, Vol. 14, no 1, p. 81-94Article in journal (Refereed) Published
Abstract [en]

Modelling and simulation of manufacturing processes may require the capability to account for localization behavior, often associated with damage/fracture. It may be unwanted localization indicating a failure in the process or, as in the case of machining and cutting, a wanted phenomenon to be controlled. The latter requires a higher accuracy regarding the modelling of the underlying physics, as well as the robustness of the simulation procedure. Two different approaches for achieving mesh-independent solutions are compared in this paper. They are the multiresolution continuum theory (MRCT) and nonlocal damage model. The MRCT theory is a general multilength-scale finite element formulation, while the nonlocal damage model is a specialized method using a weighted averaging of softening internal variables over a spatial neighborhood of the material point. Both approaches result in a converged finite element solution of the localization problem upon mesh refinement. This study compares the accuracy and robustness of their numerical schemes in implicit finite element codes for the plane strain shear deformation test case. Final remarks concerning ease of implementation of the methods in commercial finite element packages are also given.

National Category
Other Materials Engineering
Research subject
Material Mechanics
Identifiers
urn:nbn:se:ltu:diva-3403 (URN)10.1615/IntJMultCompEng.2016016322 (DOI)000374274000006 ()2-s2.0-84963719840 (Scopus ID)13b0c7c1-e817-4a05-82b9-e5bdf5fc5bc2 (Local ID)13b0c7c1-e817-4a05-82b9-e5bdf5fc5bc2 (Archive number)13b0c7c1-e817-4a05-82b9-e5bdf5fc5bc2 (OAI)
Note
Validerad; 2016; Nivå 2; 20160418 (oluabi)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-2544-9168

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