Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 121) Show all publications
Larsson, S., Pålsson, B., Parian, M. & Jonsén, P. (2020). A novel approach for modelling of physical interactions between slurry, grinding media and mill structure in wet stirred media mills. Minerals Engineering, 148, Article ID 106180.
Open this publication in new window or tab >>A novel approach for modelling of physical interactions between slurry, grinding media and mill structure in wet stirred media mills
2020 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 148, article id 106180Article in journal (Refereed) Published
Abstract [en]

Wet comminution is an important process in the mineral processing industry. Modelling of wet comminution in stirred media mills requires the simultaneous modelling of grinding media, a moving internal stirrer, and slurry. In the present study, a novel approach for modelling the physical interactions between slurry, grinding media and mill structure in a stirred media mill is presented. The slurry is modelled with the particle finite element method (PFEM). The grinding media is modelled using the discrete element method (DEM) and the mill structure is modelled using the finite element method (FEM). The interactions between slurry, grinding media and mill structure are modelled by two-way couplings between the PFEM, the DEM and the FEM models. The coupled model of the present study is used to predict the motion of slurry and grinding media, and to calculate the power draw during wet comminution in a pilot scale horizontal stirred media mill. Furthermore, the model is used to compare a Newtonian and a non-Newtonian model of the slurry, where the non-Newtonian model is used to capture experimentally observed shear-thinning. The coupled PFEM-DEM-FEM model preserves the robustness and efficiency of each of the methods and it gives the possibility to use large time increments for the fluid, greatly reducing the computational expense. The coupled model of the present work provide information on the complex dynamics of slurry and grinding media. The numerical model is shown to be a useful tool for increasing the knowledge and understanding of wet comminution in stirred media mills.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Particle finite element method, Discrete element method, Coupled models, Stirred media mills
National Category
Applied Mechanics Metallurgy and Metallic Materials
Research subject
Mineral Processing; Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-73198 (URN)10.1016/j.mineng.2019.106180 (DOI)
Note

Validerad;2020;Nivå 2;2020-02-04 (johcin)

Available from: 2019-03-14 Created: 2019-03-14 Last updated: 2020-02-04Bibliographically approved
Larsson, S., Rodriguez Prieto, J. M., Gustafsson, G., Häggblad, H.-Å. & Jonsén, P. (2020). The particle finite element method for transient granular material flow: modelling and validation. Computational Particle Mechanics
Open this publication in new window or tab >>The particle finite element method for transient granular material flow: modelling and validation
Show others...
2020 (English)In: Computational Particle Mechanics, ISSN 2196-4378Article in journal (Refereed) Epub ahead of print
Abstract [en]

The prediction of transient granular material flow is of fundamental industrial importance. The potential of using numerical methods in system design for increasing the operating efficiency of industrial processes involving granular material flow is huge. In the present study, a numerical tool for modelling dense transient granular material flow is presented and validated against experiments. The granular materials are modelled as continuous materials using two different constitutive models. The choice of constitutive models is made with the aim to predict the mechanical behaviour of a granular material during the transition from stationary to flowing and back to stationary state. The particle finite element method (PFEM) is employed as a numerical tool to simulate the transient granular material flow. Use of the PFEM enables a robust treatment of large deformations and free surfaces. The fundamental problem of collapsing rectangular columns of granular material is studied experimentally employing a novel approach for in-plane velocity measurements by digital image correlation. The proposed numerical model is used to simulate the experimentally studied column collapses. The model prediction of the in-plane velocity field during the collapse agrees well with experiments.

Place, publisher, year, edition, pages
Springer, 2020
Keywords
Particle finite element method, Transient granular material flow, Constitutive modelling, Strain-rate-dependent strength, Digital image correlation
National Category
Applied Mechanics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-73197 (URN)10.1007/s40571-020-00317-6 (DOI)
Available from: 2019-03-14 Created: 2019-03-14 Last updated: 2020-02-17
Jonsén, P., Svanberg, A., Ramirez, G., Casellas, D., Hernández, R., Marth, S., . . . Oldenburg, M. (2019). A Novel Method for Modelling of Cold Cutting of Microstructurally Tailored Hot Formed Components. In: Mats Oldenburg, Jens Hardell, Daniel Casellas (Ed.), CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, 2019: . Paper presented at CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, Luleå, Sweden, June 2nd to 5th 2019 (pp. 645-652). , 7
Open this publication in new window or tab >>A Novel Method for Modelling of Cold Cutting of Microstructurally Tailored Hot Formed Components
Show others...
2019 (English)In: CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, 2019 / [ed] Mats Oldenburg, Jens Hardell, Daniel Casellas, 2019, Vol. 7, p. 645-652Conference paper, Published paper (Refereed)
Abstract [en]

In the last decade, hot metal forming of advanced high strength steel (AHSS) have improved passenger safety and open possibilities for lightweight design. Hot metal forming can be applied to locally tailor the microstructure of components and gradual vary mechanical properties to improve crash resistance behaviour and optimized weight for e.g. safety related parts. Sometimes post punching or trimming must be done on hardened parts. Such conditions induce damage and fractures in the trimmed edge. Another issue is that high pressures are required in cutting operations due to the high yield stress of press hardened parts, which accelerate wear and produce premature fracture in tools. Optimizing cutting operations to minimize damage and wear are essentials and numerical simulations of cutting operations can be of good assistance. One of the main challenges in the numerical modelling consists of numerically be able to treat the extremely large deformation occurring in the cutting zone. A second challenge is to find suitable failure models. In this work, the punching process of soft and hard microstructures obtained by press hardening is experimentally studied, but also modelled with a combination of smoothed particle Galerkin (SPG) method and finite element method (FEM). Laboratory punching tests with different clearance values were carried out using sheets of different fracture strengths. All experimental cases are numerically modelled. Validation is conducted by comparing numerical results with experimental measurements of punch force and displacement. In addition, morphology of the final cutting edges from both real and virtual are compared. Numerical results show good agreement against experimental measurements. Furthermore, the combined method gives robust-ness and stability as it can handle large deformations efficiently.

National Category
Applied Mechanics
Identifiers
urn:nbn:se:ltu:diva-75748 (URN)
Conference
CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, Luleå, Sweden, June 2nd to 5th 2019
Available from: 2019-08-29 Created: 2019-08-29 Last updated: 2019-08-29
Frómenta, D., Parareda, S., Lara, A., Casellas, D., Pujante, J., Jonsén, P., . . . Oldenburg, M. (2019). Fracture Toughness Evaluation of Thick Press Hardened 22MnB5 Sheets for High Crash Performance Applications in Trucks. In: Mats Oldenburg, Jens Hardell, Daniel Casellas (Ed.), CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, 2019: . Paper presented at CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, Luleå, Sweden, June 2nd to 5th 2019 (pp. 113-121).
Open this publication in new window or tab >>Fracture Toughness Evaluation of Thick Press Hardened 22MnB5 Sheets for High Crash Performance Applications in Trucks
Show others...
2019 (English)In: CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, 2019 / [ed] Mats Oldenburg, Jens Hardell, Daniel Casellas, 2019, p. 113-121Conference paper, Published paper (Refereed)
National Category
Applied Mechanics
Identifiers
urn:nbn:se:ltu:diva-75751 (URN)
Conference
CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, Luleå, Sweden, June 2nd to 5th 2019
Available from: 2019-08-29 Created: 2019-08-29 Last updated: 2019-08-29
Ramanenka, D., Gustafsson, G. & Jonsén, P. (2019). Influence of heating and cooling rate on the stress state of the brick lining in a rotary kiln using finite element simulations. Engineering Failure Analysis, 105, 98-109
Open this publication in new window or tab >>Influence of heating and cooling rate on the stress state of the brick lining in a rotary kiln using finite element simulations
2019 (English)In: Engineering Failure Analysis, ISSN 1350-6307, E-ISSN 1873-1961, Vol. 105, p. 98-109Article in journal (Refereed) Published
Abstract [en]

Rotary kilns for iron-ore pellets production are highly dependent on a well-functioned refractory brick lining. To improve the long-term capability of the lining, in-situ observations of the bricks' performance are desired, however, the harsh environment inside the rotary kiln makes it difficult or nearly impossible to study the lining during operation. By using numerical simulations as a tool, some of the problems encountered by the brick lining can be studied without limitation of the extreme conditions.

In this work, stress state of the lining was studied under the influence of different heating and cooling rates, and different brick compaction cases. A finite element model was created for conducting the numerical simulations. The numerical model was calibrated for transient heat transfer. Temperature dependent material properties of the bricks and casing were used as input. The heating and cooling was controlled by temperature prescription on the boundary of the brick lining, while brick lining compaction by defining relative position of the bricks in axial and radial directions.

The conducted numerical simulations showed that considerable tensile stress may appear in a large area of the brick during initial heating stage. The large tensile area corresponds well with the typical circumferential cracks experienced by the bricks. It was demonstrated that the compressive stresses counteract the development of tensile stresses. However, the compressive stresses may become very large in the initial stage of heating. The positive effect of lower heating rate was considerable on the tensile stresses, while influence on the compressive stresses was almost unnoticed. The hypothetical cooling rates showed that very high tensile stresses may occur on the surface of the bricks, potentially leading to surface spalling. Furthermore, it was demonstrated that axial compaction is highly important on the stress development in the lining, which, may not always be followed in practice. As a general conclusion, it is recommended to always achieve a tight compaction of the brick lining and to take measures for lowering the heating and cooling rates.

The conducted work exemplifies behaviour of the brick lining for realistic heat transfer and material properties. The insight into the behaviour gives possibilities to make adjustments and directed investments for lowering risk of brick lining failure.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
High temperature, Stress state, Refractory brick lining, Rotary kiln, Finite element method
National Category
Applied Mechanics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-68375 (URN)10.1016/j.engfailanal.2019.06.031 (DOI)000496188200009 ()
Note

Validerad;2019;Nivå 2;2019-07-08 (johcin)

Available from: 2018-04-16 Created: 2018-04-16 Last updated: 2019-11-29Bibliographically approved
Golling, S., Frometa, D., Casellas, D. & Jonsén, P. (2019). Influence of microstructure on the fracture toughness of hot stamped boron steel. Materials Science & Engineering: A, 743, 529-539
Open this publication in new window or tab >>Influence of microstructure on the fracture toughness of hot stamped boron steel
2019 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 743, p. 529-539Article in journal (Refereed) Published
Abstract [en]

The automotive industry's desire for weight reduction while maintaining crashworthiness demands development of materials and material properties within the economic framework of consumers. The industrial process of hot stamping provides a technique to utilize steel in an efficient way. In hot stamping, microstructural characteristics of a steel blank are influenced by controlling the cooling rate. Hot stamping has become a prevalent method for lightweight solutions in car bodies without sacrificing passenger safety. The process of hot stamping applies sequential forming and quenching in a single production step. During the cooling of the blank, various microstructures can be formed depending on the cooling rate or holding temperature. Special tooling allows the application of different cooling rates within the same blank. Thus, the microstructure and mechanical properties can be influenced in designated areas of a blank.

Fracture toughness properties of sheet metal are necessary to better understand fracture initiation and crack propagation during crash loading as well as improve crashworthiness predictions. This paper focus on fracture toughness of low-alloyed boron steel sheet common in the automotive industry. A heat treatment process is used to form different microstructures, predominately consisting of one single phase or mixed microstructures with two distinct phases. The fracture toughness of the present microstructures is evaluated using the Essential Work of Fracture methodology. Results are discussed in terms of the different microstructures obtained and the consequent part performance.

Results show a strong connection between microstructure and fracture toughness. The bainitic grade shows favorable fracture toughness while a mixed microstructure of bainite and martensite shows a very brittle fracture behavior. A post heat treatment in the form of paint bake curing shows a negligible effect on fracture toughness of martensite.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Fracture toughness, Essential work of fracture, Heat treatment, 22MnB5, Hot stamping
National Category
Applied Mechanics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-71682 (URN)10.1016/j.msea.2018.11.080 (DOI)000456891500060 ()2-s2.0-85057313484 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-01-31 (johcin) 

Available from: 2018-11-20 Created: 2018-11-20 Last updated: 2019-09-13Bibliographically approved
Hammarberg, S., Kajberg, J. & Jonsén, P. (2019). Modeling of Ultra High Strength Steel Sandwiches with Lightweight Cores. In: Mats Oldenburg, Jens Hardell, Daniel Casellas (Ed.), CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel: . Paper presented at CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, Luleå, Sweden, June 2nd to 5th 2019 (pp. 313-320).
Open this publication in new window or tab >>Modeling of Ultra High Strength Steel Sandwiches with Lightweight Cores
2019 (English)In: CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel / [ed] Mats Oldenburg, Jens Hardell, Daniel Casellas, 2019, p. 313-320Conference paper, Published paper (Refereed)
National Category
Applied Mechanics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-75752 (URN)
Conference
CHS² 2019 - 7th International Conference on Hot Sheet Metal Forming of High Performance Steel, Luleå, Sweden, June 2nd to 5th 2019
Available from: 2019-08-29 Created: 2019-08-29 Last updated: 2019-08-29
Rodriguez Prieto, J. M., Carbonell, J. & Jonsén, P. (2019). Numerical Methods for the Modelling of Chip Formation. Archives of Computational Methods in Engineering
Open this publication in new window or tab >>Numerical Methods for the Modelling of Chip Formation
2019 (English)In: Archives of Computational Methods in Engineering, ISSN 1134-3060, E-ISSN 1886-1784Article in journal (Refereed) Epub ahead of print
Abstract [en]

The modeling of metal cutting has proved to be particularly complex due to the diversity of physical phenomena involved, including thermo-mechanical coupling, contact/friction and material failure. During the last few decades, there has been significant progress in the development of numerical methods for modeling machining operations. Furthermore, the most relevant techniques have been implemented in the relevant commercial codes creating tools for the engineers working in the design of processes and cutting devices. This paper presents a review on the numerical modeling methods and techniques used for the simulation of machining processes. The main purpose is to identify the strengths and weaknesses of each method and strategy developed up-to-now. Moreover the review covers the classical Finite Element Method covering mesh-less methods, particle-based methods and different possibilities of Eulerian and Lagrangian approaches.

Place, publisher, year, edition, pages
Springer, 2019
National Category
Applied Mechanics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-72672 (URN)10.1007/s11831-018-09313-9 (DOI)
Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2019-01-24
Jonsén, P., Hammarberg, S., Pålsson, B. & Lindkvist, G. (2019). Preliminary validation of a new way to model physical interactions between pulp, charge and mill structure in tumbling mills. Minerals Engineering, 130, 76-84
Open this publication in new window or tab >>Preliminary validation of a new way to model physical interactions between pulp, charge and mill structure in tumbling mills
2019 (English)In: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 130, p. 76-84Article in journal (Refereed) Published
Abstract [en]

Modelling of wet grinding in tumbling mills is an interesting challenge. A key factor is that the pulp fluid and its simultaneous interactions with both the charge and the mill structure have to be handled in a computationally efficient way. In this work, the pulp fluid is modelled with a Lagrange based method based on the particle finite element method (PFEM) that gives the opportunity to model free surface flow. This method gives robustness and stability to the fluid model and is efficient as it gives possibility to use larger time steps. The PFEM solver can be coupled to other solvers as in this case both the finite element method (FEM) solver for the mill structure and the DEM solver for the ball charge. The combined PFEM-DEM-FEM model presented here can predict charge motion and responses from the mill structure, as well as the pulp liquid flow and pressure. All cases presented here are numerically modelled and validated against experimentally measured driving torque signatures from an instrumented small-scale batch ball mill equipped with a torque meter and charge movements captured from high-speed video. Numerical results are in good agreement with experimental torque measurements and the PFEM solver also improves on efficiency and robustness for solving charge movements in wet tumbling mill systems.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Grinding, Modelling, Simulation, Validation
National Category
Applied Mechanics Metallurgy and Metallic Materials
Research subject
Solid Mechanics; Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-71226 (URN)10.1016/j.mineng.2018.10.013 (DOI)000452937000010 ()2-s2.0-85054850385 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-10-16 (svasva)

Available from: 2018-10-16 Created: 2018-10-16 Last updated: 2019-02-01Bibliographically approved
Larsson, S., Pålsson, B., Parian, M. & Jonsén, P. (2019). Preliminary validation of a stirred media mill model. In: : . Paper presented at Conference in Minerals Engineering 2019.
Open this publication in new window or tab >>Preliminary validation of a stirred media mill model
2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Wet fine grinding is an important process in the minerals industry. Modelling of wet grinding in stirred media mills is challenging since it requires the simultaneous modelling of grinding media consisting of a huge number of small grinding bodies, moving internal stirrer, and the pulp fluid. All of them in interaction with each other. In the present study, wet grinding in a stirred media mill is studied using coupled incompressible computational fluid dynamics (ICFD) and discrete element method (DEM) and finite element method (FEM) simulations. The DEM is used to model the grinding media, and the pulp fluid flow is modelled using the ICFD. Moreover, the FEM is used to model the structure of the mill body and is in combination with DEM used to estimate the wear rate in the system. The present implementation of the coupled ICFD-DEM-FEM preserves the robustness and efficiency of both methods, and it gives the possibility to use large time steps for the fluid with very low computation times.

National Category
Applied Mechanics Metallurgy and Metallic Materials
Research subject
Solid Mechanics; Mineral Processing
Identifiers
urn:nbn:se:ltu:diva-72951 (URN)
Conference
Conference in Minerals Engineering 2019
Available from: 2019-02-19 Created: 2019-02-19 Last updated: 2019-02-22
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0910-7990

Search in DiVA

Show all publications