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Jonsén, Pär, Chair ProfessorORCID iD iconorcid.org/0000-0003-0910-7990
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Publications (10 of 169) Show all publications
Stenström, C., Eriksson, K., Bobaru, F., Golling, S. & Jonsén, P. (2023). The essential work of fracture in peridynamics. International Journal of Fracture, 242(2), 129-152
Open this publication in new window or tab >>The essential work of fracture in peridynamics
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2023 (English)In: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 242, no 2, p. 129-152Article in journal (Refereed) Published
Abstract [en]

In this work, the essential work of fracture (EWF) method is introduced for a peridynamic (PD) material model to characterize fracture toughness of ductile materials. First, an analytical derivation for the path-independence of the PD J-integral is provided. Thereafter, the classical J-integral and PD J-integral are computed on a number of analytical crack problems, for subsequent investigation on how it performs under large scale yielding of thin sheets. To represent a highly nonlinear elastic behavior, a new adaptive bond stiffness calibration and a modified bond-damage model with gradual softening are proposed. The model is employed for two different materials: a lower-ductility bainitic-martensitic steel and a higher-ductility bainitic steel. Up to the start of the softening phase, the PD model recovers the experimentally obtained stress-strain response of both materials. Due to the high failure sensitivity on the presence of defects for the lower-ductility material, the PD model could not recover the experimentally obtained EWF values. For the higher-ductility bainitic material, the PD model was able to match very well the experimentally obtained EWF values. Moreover, the J-integral value obtained from the PD model, at the absolute maximum specimen load, matched the corresponding EWF value.

Place, publisher, year, edition, pages
Springer, 2023
Keywords
Peridynamics, J-integral, Essential work of fracture, Nonlocal model, Fracture, Crack tip, Center cracked tension, Double edge notched tension, Fracture toughness, Softening, Thin sheet, Peridynamik
National Category
Applied Mechanics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-98645 (URN)10.1007/s10704-023-00705-y (DOI)001025601000001 ()2-s2.0-85164524536 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-08-18 (marisr);

License fulltext: CC-BY

Available from: 2023-06-20 Created: 2023-06-20 Last updated: 2023-09-05Bibliographically approved
Suarez, L., Jonsén, P. & Kajberg, J. (2023). Valorization of Air-Cooled EAF Manganese Slag in Comminution Processes: an Investigation into the Breakage Characterization. Mining, Metallurgy & Exploration
Open this publication in new window or tab >>Valorization of Air-Cooled EAF Manganese Slag in Comminution Processes: an Investigation into the Breakage Characterization
2023 (English)In: Mining, Metallurgy & Exploration, ISSN 2524-3462Article in journal (Refereed) Epub ahead of print
Abstract [en]

In recent years, slag, a residue from pyrometallurgical processes, has become more attractive in circular economy frameworks to increase the efficient use of resources throughout the life cycle of steel products and help in the reduction of carbon emissions. Its applicability is strongly dependent on the particle size, and therefore, the optimization of breaking processes should be approached by increasing the knowledge of the dynamics of slag to promote fracture. Increasing the knowledge on the mechanical response of manganese slag opens up the potential for the development of cost-effective numerical models, e.g., constitutive models based on inverse engineering calibration frameworks or digital twins. In this study, rate-dependent tests of manganese slag have been performed using a split Hopkinson pressure bar device for testing its dynamic mechanical response. In order to obtain information about the crack initiation and fracture process, 2D ultra-high speed imaging was implemented with a sampling frequency of 663,200 fps for diametrically loaded specimens. Full-field deformation measurements using digital image correlation (DIC) techniques showed a staggered fracture process where failure points on mechanical response curves vary due to the internal events happening in the material. Localized frictional occurrences and inertial effects acting inside the pre-cracked matrix have a strong effect on the global mechanical response, and therefore, a great variability of strengths was obtained.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
Brazilian disc, SHPB, Ultra-high speed imaging, DIC, Slag
National Category
Other Mechanical Engineering Metallurgy and Metallic Materials
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-102325 (URN)10.1007/s42461-023-00856-5 (DOI)
Funder
EU, Horizon 2020
Note

CC BY 4.0 License

Funder: EIT Raw Materials “GREENY,” Grinding Energy Efficiency, (grant number 18009)

Available from: 2023-11-06 Created: 2023-11-06 Last updated: 2023-11-06
Wessling, A., Larsson, S., Jonsén, P. & Kajberg, J. (2022). A Brittle and Heterogeneous Bonded Discrete Element Model of Wide Applicability. In: Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson (Ed.), Svenska Mekanikdagar 2022: . Paper presented at Svenska Mekanikdagarnam2022, Luleå, Sweden, June 15-16, 2022. Luleå tekniska universitet
Open this publication in new window or tab >>A Brittle and Heterogeneous Bonded Discrete Element Model of Wide Applicability
2022 (English)In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå tekniska universitet, 2022Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2022
National Category
Other Materials Engineering
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-92496 (URN)
Conference
Svenska Mekanikdagarnam2022, Luleå, Sweden, June 15-16, 2022
Available from: 2022-08-16 Created: 2022-08-16 Last updated: 2023-09-05Bibliographically approved
Wessling, A., Larsson, S., Jonsén, P. & Kajberg, J. (2022). A statistical DEM approach for modelling heterogeneous brittle materials. Computational Particle Mechanics, 9(4), 615-631
Open this publication in new window or tab >>A statistical DEM approach for modelling heterogeneous brittle materials
2022 (English)In: Computational Particle Mechanics, ISSN 2196-4378, Vol. 9, no 4, p. 615-631Article in journal (Refereed) Published
Abstract [en]

By utilizing numerical models and simulation, insights about the fracture process of brittle heterogeneous materials can be gained without the need for expensive, difficult, or even impossible, experiments. Brittle and heterogeneous materials like rocks usually exhibit a large spread of experimental data and there is a need for a stochastic model that can mimic this behaviour. In this work, a new numerical approach, based on the Bonded Discrete Element Method, for modelling of heterogeneous brittle materials is proposed and evaluated. The material properties are introduced into the model via two main inputs. Firstly, the grains are constructed as ellipsoidal subsets of spherical discrete elements. The sizes and shapes of these ellipsoidal subsets are randomized, which introduces a grain shape heterogeneity Secondly, the micromechanical parameters of the constituent particles of the grains are given by the Weibull distribution. The model was applied to the Brazilian Disc Test, where the crack initiation, propagation, coalescence and branching could be investigated for different sets of grain cement strengths and sample heterogeneities. The crack initiation and propagation was found to be highly dependent on the level of heterogeneity and cement strength. Specifically, the amount of cracks initiating from the loading contact was found to be more prevalent for cases with higher cement strength and lower heterogeneity, while a more severe zigzag shaped crack pattern was found for the cases with lower cement strength and higher heterogeneity. Generally, the proposed model was found to be able to capture typical phenomena associated with brittle heterogeneous materials, e.g. the unpredictability of the strength in tension and crack properties.

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
Bonded DEM, Heterogeneous brittle materials, Fracture, Brazilian disc, Weibull
National Category
Other Mechanical Engineering Applied Mechanics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-83907 (URN)10.1007/s40571-021-00434-w (DOI)000692075800001 ()2-s2.0-85114114019 (Scopus ID)
Projects
GEOFIT
Funder
EU, Horizon 2020, 792210
Note

Validerad;2022;Nivå 2;2022-07-26 (hanlid)

Available from: 2021-04-23 Created: 2021-04-23 Last updated: 2023-09-05Bibliographically approved
Larsson, F., Oldenburg, M. & Jonsén, P. (2022). A Testing Methodology for Hot Rolled High Strength Steels Under Warm Forming Conditions. In: Mats Oldenburg; Jens Hardell; Daniel Casellas (Ed.), Hot Sheet Metal Forming of High-Performance Steel: proceedings: . Paper presented at 8th International Conference Hot Sheet Metal Forming of High-Performance Steel (CHS2 2022), Barcelona, Spain, May 30-June 2, 2022 (pp. 411-418). Wissenschaftliche Scripten
Open this publication in new window or tab >>A Testing Methodology for Hot Rolled High Strength Steels Under Warm Forming Conditions
2022 (English)In: Hot Sheet Metal Forming of High-Performance Steel: proceedings / [ed] Mats Oldenburg; Jens Hardell; Daniel Casellas, Wissenschaftliche Scripten , 2022, p. 411-418Conference paper, Published paper (Refereed)
Abstract [en]

For the reduction of the environmental footprint of Heavy-Duty vehicles (HDV), lighter chassiscomponents can be considered. A lighter HDV chassis gives the opportunity of lower fuel consumption, increased payloads, and savings of material resources. One way of achieving this, is to reduce thicknesses of components in combination of using higher strength steels. For the aim of forming UHSS into complex geometries the need to characterize thick sheet metal at elevated temperatures arises. This work aims at expanding earlier research of characterization of thinner sheet metal and create a testing methodology for tensile tests of 7 mm thick steel sheets at elevated temperatures. An experimental methodology for evaluating high strength steel under warm conditions have been developed and demonstrated. A Digital Image Correlation system is used to extract strain fields for all three testing temperatures. This together with an automatized induction system pre-defined temperature cycles are applied. When the desired Hollomon-Jaffe constant is obtained the tensile test is executed. The methodology shows promising results with good repeatability of stress-strain curves. The methodology shows good stability and are promising for future development and investigations of high strength steels under warm forming conditions.

Place, publisher, year, edition, pages
Wissenschaftliche Scripten, 2022
National Category
Other Mechanical Engineering
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-92195 (URN)
Conference
8th International Conference Hot Sheet Metal Forming of High-Performance Steel (CHS2 2022), Barcelona, Spain, May 30-June 2, 2022
Note

ISBN för värdpublikation: 978-3-95735-150-0

Available from: 2022-07-18 Created: 2022-07-18 Last updated: 2023-09-07Bibliographically approved
Pålsson, B. I., Parian, M., Larsson, S. & Jonsén, P. (2022). An attempt to a full energy balance for a pilot-scale stirred media mill. In: IMPC Asia-Pacific 2022 Conference Proceedings: . Paper presented at IMPC Asia-Pacific 2022, Melbourne, Australia, August 22-24, 2022 (pp. 266-273). The Australian Institute of Mining and Metallurgy
Open this publication in new window or tab >>An attempt to a full energy balance for a pilot-scale stirred media mill
2022 (English)In: IMPC Asia-Pacific 2022 Conference Proceedings, The Australian Institute of Mining and Metallurgy , 2022, p. 266-273Conference paper, Published paper (Refereed)
Abstract [en]

The question of effective energy utilisation in grinding mills is not new. There are several conflicting arguments about tumbling mills, whether the efficiency is around one per cent or maybe ten per cent, or even much lower. The energy not used is assumed to be lost as heating of the pulp, the grinding mill body, the charge, generation of shockwaves and vibrations, etc. Stirred media mills on the other hand are generally considered to have better energy utilisation, but their energy efficiency is still not that clear. To shed some light on this a pilot-scale, wet stirred media mill was investigated over a range of operating conditions. The wet stirred media mill is a Drais PMH 5 TEX pearl mill fitted with an electric motor at 11 kW. It has been investigated over a range of operating conditions to try to balance the dissemination of the input energy in forms of the net grinding energy, mechanical energy losses, and the heating transferred to the pulp, the mill, the charge, and the cooling water. It is found that approximately 20 – 40 per cent of the input energy accounts for the grinding process. Also, that the difference between gross and net input electrical energy is mainly disseminated as heating of the pulp and cooling water. Mechanical energy losses appear to be much smaller than the heating effects. The use of a dispersant seems to mainly influence the heating effect.

Place, publisher, year, edition, pages
The Australian Institute of Mining and Metallurgy, 2022
Keywords
Energy balance, stirred media mill
National Category
Energy Engineering
Research subject
Mineral Processing; Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-92705 (URN)
Conference
IMPC Asia-Pacific 2022, Melbourne, Australia, August 22-24, 2022
Projects
Stirred media mill performance and grinding wear prediction
Funder
Vinnova, 2017-05463
Note

ISBN för värdpublikation: 978-1-922395-08-5

Available from: 2022-08-30 Created: 2022-08-30 Last updated: 2023-09-05Bibliographically approved
Hammarberg, S., Kajberg, J., Larsson, S., Moshfegh, R. & Jonsén, P. (2022). Calibration of orthotropic plasticity- and damage models for micro-sandwich materials. SN Applied Sciences, 4(6), Article ID 182.
Open this publication in new window or tab >>Calibration of orthotropic plasticity- and damage models for micro-sandwich materials
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2022 (English)In: SN Applied Sciences, ISSN 2523-3963, E-ISSN 2523-3971, Vol. 4, no 6, article id 182Article in journal (Refereed) Published
Abstract [en]

Sandwich structures are commonly used to increase bending-stiffness without significantly increasing weight. In particular, micro-sandwich materials have been developed with the automotive industry in mind, being thin and formable. In the present work, it is investigated if micro-sandwich materials may be modeled using commercially available material models, accounting for both elasto-plasticity and fracture. A methodology for calibration of both the constitutive- and the damage model of micro-sandwich materials is presented. To validate the models, an experimental T-peel test is performed on the micro-sandwich material and compared with the numerical models. The models are found to be in agreement with the experimental data, being able to recreate the force response as well as the fracture of the micro-sandwich core.

Place, publisher, year, edition, pages
Springer Nature, 2022
Keywords
Micro sandwich, Hybrix, Lightweight, Modeling, T-peel test
National Category
Composite Science and Engineering
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-85075 (URN)10.1007/s42452-022-05060-6 (DOI)000798485800004 ()2-s2.0-85130368530 (Scopus ID)
Funder
EU, Horizon 2020, 814517 Form-Planet
Note

Validerad;2022;Nivå 2;2022-06-03 (hanlid)

Available from: 2021-06-08 Created: 2021-06-08 Last updated: 2023-09-05Bibliographically approved
Wessling, A., Kajberg, J., Larsson, S., Jonsén, P., Ramírez Sandoval, G. & Vilaseca Llosada, M. (2022). Discrete Element Modelling of Rock Drilling. In: European Geothermal Congress 2022: . Paper presented at European Geothermal Congress 2022, October 17-21, 2022, Berlin, Germany. , Article ID 272.
Open this publication in new window or tab >>Discrete Element Modelling of Rock Drilling
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2022 (English)In: European Geothermal Congress 2022, 2022, article id 272Conference paper, Published paper (Refereed)
Abstract [en]

Percussive rotary drilling is recognized as the mostefficient method for hard rock drilling. Despite clearadvantages over conventional rotary methods, there arestill some uncertainties associated with percussivedrilling. For geothermal applications, drilling accountsfor a large portion of the total cost. Specifically, thewear of drill bits when drilling in hard rock is apredominant cost factor and drilling parameters areoften based on the experience of the field operator.Within the framework of the H2020 project GEOFIT,numerical simulations of percussive drilling areperformed in order to evaluate the rock drilling processand gain insight about the trade-off between wear andRate of Penetration (ROP). In the simulations, the rockmaterial was represented by the Bonded DiscreteElement Method (BDEM), the drill bit by the FiniteElement Method (FEM), the drilling fluid by theParticle Finite Element Method (PFEM) and theabrasive wear on the surface of the drill bit wasrepresented by Archard’s wear law. The drillingsimulations were conducted for two rock materials; asedimentary rock material corresponding to what wasfound when drilling at the GEOFIT pilot site in AranIslands, Ireland, and a harder reference rock similar togranite. The results show that, at a drill bit impact forceof 10 kN, the ROP in the sedimentary rock was 6.3times faster than for granite. When increasing theimpact force to 40 and 50 kN, however, the ROP for thesedimentary rock is only 1.9 and 1.6 times faster,respectively. Furthermore, the wear rate decreased withincreased impact force when drilling in the granite rock.For the sedimentary rock, however, the loadingresulting in the best trade-off between abrasive wearand ROP was the second highest loading of 40 kN,which suggests that an increase in impact energy mayincrease the rate of penetration but may not beeconomically motivated.

National Category
Other Civil Engineering
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-96967 (URN)978-2-9601946-2-3 (ISBN)
Conference
European Geothermal Congress 2022, October 17-21, 2022, Berlin, Germany
Projects
GEOFIT
Available from: 2023-05-02 Created: 2023-05-02 Last updated: 2023-09-05Bibliographically approved
Gustafsson, D., Parareda, S., Jonsén, P., Kajberg, J. & Olsson, E. (2022). Effect Of Cutting Clearance And Sandblasting On Fatigue Of Thick CP800 Steel Sheets. In: Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson (Ed.), Svenska Mekanikdagar 2022: . Paper presented at Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022. Luleå tekniska universitet
Open this publication in new window or tab >>Effect Of Cutting Clearance And Sandblasting On Fatigue Of Thick CP800 Steel Sheets
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2022 (English)In: Svenska Mekanikdagar 2022 / [ed] Pär Jonsén; Lars-Göran Westerberg; Simon Larsson; Erik Olsson, Luleå tekniska universitet, 2022Conference paper, Oral presentation with published abstract (Refereed)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2022
National Category
Mechanical Engineering
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-93157 (URN)
Conference
Svenska Mekanikdagarna 2022, Luleå, Sweden, June 15-16, 2022
Available from: 2022-09-21 Created: 2022-09-21 Last updated: 2023-09-05Bibliographically approved
Gustafsson, D., Parareda, S., Jonsén, P., Kajberg, J. & Olsson, E. (2022). Effect of cutting clearance and sandblasting on fatigue of thick CP800 steel sheets for heavy-duty vehicles. In: Mats Oldenburg; Jens Hardell; Daniel Casellas (Ed.), Hot Sheet Metal Forming of High-Performance Steel: proceedings: . Paper presented at 8th International Conference on Hot Sheet Metal Forming of High Performance Steel (CHS² 2022), 30 May-2 June, 2022, Barcelona, Spain (pp. 315-322). Wissenschaftliche Scripten
Open this publication in new window or tab >>Effect of cutting clearance and sandblasting on fatigue of thick CP800 steel sheets for heavy-duty vehicles
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2022 (English)In: Hot Sheet Metal Forming of High-Performance Steel: proceedings / [ed] Mats Oldenburg; Jens Hardell; Daniel Casellas, Wissenschaftliche Scripten , 2022, p. 315-322Conference paper, Published paper (Refereed)
Abstract [en]

Effect from manufacturing processes on fatigue properties of high-strength thick steel sheets have gained increased attention the recent years, due to new demands on the heavy-duty vehicle (HDV) industry to reduce the carbon footprint. The aim of this study is to add knowledge of the effect of shear cutting clearance on the fatigue behaviour of complex phase CP800 thick steel sheets. In addition, sandblasting and its effect on the fatigue properties are studied. Service loads are fluctuating loads acting on chassis component making fatigue an important failure mode. The fatigue strength usually follows the yield strength of the material and hence weight could in theory be saved by using steels of higher strength. However, in the presence of edge defects this relation does not necessarily hold, this leads to large safety factors of the design and under-utilization of the high-strength material. Thus, an increased knowledge about the effect from manufacturing processes on fatigue properties is important for the quest to achieve weight reduction. This is particularly true for thick sheets which, to the best of our knowledge, are less investigated than their thinner counterparts, but of high importance for the HDV development.

 

In this paper, empirical results from fatigue testing of complex phase steel CP800, subjected to punching and trimming, are presented. Results for different cutting clearances are compared as well as the effect of sandblasting. A fast fatigue testing method called Rapid fatigue test based on stiffness evolution is utilized. The results show the improvement obtained by using sandblasting as well as illustrating the effect of different cutting clearances. These results can be used as a guidance for design and production of HDV components, where cutting clearance is set. Furthermore, the results can be used as an input for discussions whether the extra costs associated with sandblasting is motivated or not for components made from high strength, thick steel sheets.

Place, publisher, year, edition, pages
Wissenschaftliche Scripten, 2022
Keywords
fatigue, trimming, punching, cutting clearance, sandblasting
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
Solid Mechanics
Identifiers
urn:nbn:se:ltu:diva-91142 (URN)
Conference
8th International Conference on Hot Sheet Metal Forming of High Performance Steel (CHS² 2022), 30 May-2 June, 2022, Barcelona, Spain
Projects
Fatigue4Light
Funder
EU, Horizon 2020, 101006844
Note

ISBN för värdpublikation: 978-3-95735-150-0

Available from: 2022-06-09 Created: 2022-06-09 Last updated: 2023-09-05Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-0910-7990

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