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Publications (10 of 27) Show all publications
Zhang, Y., Hammam, T., Belov, I., Sjögren, T., Bakowski, M. & Nee, H. P. (2017). Thermomechanical Analysis and Characterization of a Press-Pack Structure for SiC Power Module Packaging Applications. IEEE Transactions on Components, Packaging, and Manufacturing Technology, 7(7), 1089-1100
Open this publication in new window or tab >>Thermomechanical Analysis and Characterization of a Press-Pack Structure for SiC Power Module Packaging Applications
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2017 (English)In: IEEE Transactions on Components, Packaging, and Manufacturing Technology, ISSN 2156-3950, E-ISSN 2156-3985, Vol. 7, no 7, p. 1089-1100Article in journal (Refereed) Published
Abstract [en]

This paper presents an experimental methodology for the characterization of thermomechanical displacement and friction properties in a free-floating press-pack structure, and evaluation of the tensile stress on the semiconductor die through simulation of different mechanical and thermal loading conditions. The press-pack structure consists of a single silver-metallized (1 μm) silicon carbide die (400 μm) in contact with rhodium-coated (0.4 μm) molybdenum square plates. The thermomechanical displacements in the press-pack structure have been obtained using the digital image correlation technique, and the mean random error has been $± $0.1 μm, which is approximately 10 ppm of the measured length (10.5 mm). The developed experimental method has led to an analytical estimation of friction coefficients on the interfaces' silicon carbide-molybdenum and molybdenum-copper. The results demonstrate that the thin silver layer behaves as a solid film lubricant. A 2-D finite-element model representing the experimental setup has been implemented. The difference in displacement between measurement and simulation is less than 8%. Furthermore, the coinfluence of the design parameters on the thermomechanical performance of the stacked structure has been analyzed through simulations. Finally, design guidelines to reduce the tensile stress on the silicon carbide die have been proposed regarding free-floating press-pack power electronics packaging.

Keywords
Bars, Finite-element (FE) analysis, Friction, measurement techniques, Multichip modules, optical imaging, power electronics, Silicon carbide, stress, Temperature measurement, thermal expansion., Thermomechanical processes, Bars (metal), Carbide dies, Electronics packaging, Finite element method, Molybdenum, Silicon, Silver, Stress analysis, Stresses, Structural design, Tensile stress, Thermal expansion, Tribology, Wide band gap semiconductors, Digital image correlation technique, Experimental methodology, Measurement and simulation, Thermo-mechanical analysis, Thermo-mechanical performance, Thermomechanical process, Presses (machine tools)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-30870 (URN)10.1109/TCPMT.2017.2711272 (DOI)2-s2.0-85023771342 (Scopus ID)
Available from: 2017-09-06 Created: 2017-09-06 Last updated: 2018-08-21Bibliographically approved
Jacobsson, L., Sandström, J., Flansbjer, M., Sjögren, T. & Brander, L. (2016). ONKALO POSE Experiment - Laboratory Determination of Density, Porosity and Mechanical Anisotropy of Gneiss and Granite.
Open this publication in new window or tab >>ONKALO POSE Experiment - Laboratory Determination of Density, Porosity and Mechanical Anisotropy of Gneiss and Granite
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2016 (English)Report (Other academic)
Publisher
p. 288
Series
Posiva working report ; 31
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-27911 (URN)
Available from: 2017-01-20 Created: 2017-01-20 Last updated: 2018-08-22Bibliographically approved
Sjögren, T., Lausmaa, J., Snis, A., Engqvist, H. & Karlsson, J. (2014). Digital image correlation analysis of local strain fields on Ti6A14V manufactured by electron beam melting (ed.). Materials Science & Engineering A, 618, 456-461
Open this publication in new window or tab >>Digital image correlation analysis of local strain fields on Ti6A14V manufactured by electron beam melting
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2014 (English)In: Materials Science & Engineering A, Vol. 618, p. 456-461Article in journal (Other academic) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6630 (URN)16676 (Local ID)16676 (Archive number)16676 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2018-08-21Bibliographically approved
Karlsson, J., Sjögren, T., Snis, A., Engqvist, H. & Lausmaa, J. (2014). Digital image correlation analysis of local strain fields on Ti6Al4V manufactured by electron beam melting (ed.). Materials Science & Engineering: A, 618, 456-461
Open this publication in new window or tab >>Digital image correlation analysis of local strain fields on Ti6Al4V manufactured by electron beam melting
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2014 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 618, p. 456-461Article in journal (Refereed) Published
Abstract [en]

Additive manufacturing, or 3D-printing as it is often called, build parts in a layer-by-layer fashion. A common concern, regardless of the specific additive manufacturing technique used, is the risk of inadequate fusion between the adjacent layers which in turn may cause inferior mechanical properties. In this work, the local strain properties of titanium parts produced by Electron Beam Melting (EBM®) were studied in order to gain information about the quality of fusion of the stock powder material used in the process. By using Digital Image Correlation (DIC) the strain fields in the individual layers were analyzed, as well as the global strain behavior of the bulk material. The results show that fully solid titanium parts manufactured by EBM are homogenous and do not experience local deformation behavior, neither on local nor on a global level.

Keywords
Additive manufacturing, Characterization, Digital image correlation, Electron beam melting, Mechanical, Titanium alloys Digital image correlation analysis of local strain fields on Ti6Al4V manufactured by electron beam melting Understanding mechanisms and factors related to implant fixation, a model study of removal torque
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-27311 (URN)10.1016/j.msea.2014.09.022 (DOI)
Note

A3376

Available from: 2016-12-08 Created: 2016-12-08 Last updated: 2018-08-21Bibliographically approved
Sjögren, T. (2014). Materials performance assessment of precision cast aluminium components with novel strain analysis techniques (ed.). International Foundry Research (3), 10
Open this publication in new window or tab >>Materials performance assessment of precision cast aluminium components with novel strain analysis techniques
2014 (English)In: International Foundry Research, no 3, p. 10-Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6624 (URN)16571 (Local ID)16571 (Archive number)16571 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2018-08-21Bibliographically approved
Sjögren, T., Skoglund, P. & Moverare, J. (2013). Fatigue and strength of new grey iron alloys for brake discs (ed.). In: Konferensbidrag till 7th International on Low Cycle Conference Fatigue (LCF7): . Paper presented at Konferensbidrag till 7th International on Low Cycle Conference Fatigue (LCF7) October 9-11 i Aachen, Germany..
Open this publication in new window or tab >>Fatigue and strength of new grey iron alloys for brake discs
2013 (English)In: Konferensbidrag till 7th International on Low Cycle Conference Fatigue (LCF7), 2013Conference paper, Published paper (Other academic)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-12256 (URN)14972 (Local ID)14972 (Archive number)14972 (OAI)
Conference
Konferensbidrag till 7th International on Low Cycle Conference Fatigue (LCF7) October 9-11 i Aachen, Germany.
Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2018-08-21Bibliographically approved
Sjögren, T., Skoglund, P. & Moverare, J. (2013). Fatigue and strength of new grey iron alloys for brake discs (ed.). In: : . Paper presented at 7th International on Low cycle Conference Fatigue (LCF7) October 9-11 2013, Aachen, Germany.
Open this publication in new window or tab >>Fatigue and strength of new grey iron alloys for brake discs
2013 (English)Conference paper, Published paper (Refereed)
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-12340 (URN)16072 (Local ID)16072 (Archive number)16072 (OAI)
Conference
7th International on Low cycle Conference Fatigue (LCF7) October 9-11 2013, Aachen, Germany
Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2018-08-21Bibliographically approved
Sjögren, T., Diaconu, V. L., Skoglund, P. & Diószegi, A. (2013). Stress relaxation of compacted graphite iron alloyed with molybdenum (ed.). International Journal of Cast Metal Research, 26(1), 51-57
Open this publication in new window or tab >>Stress relaxation of compacted graphite iron alloyed with molybdenum
2013 (English)In: International Journal of Cast Metal Research, Vol. 26, no 1, p. 51-57Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6438 (URN)14134 (Local ID)14134 (Archive number)14134 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2018-08-21Bibliographically approved
Sjögren, T., Autio, A., Odnegård, K. & Andersson, H. (2012). Analysis of strains in cast iron joints using finite element simulations and digital image correlation techniques (ed.). In: 70th World Foundry Congress 2012, WFC 2012: . Paper presented at 70th World Foundry Congress 2012, WFC 2012, April 25-27, Monterrey, Mexico.
Open this publication in new window or tab >>Analysis of strains in cast iron joints using finite element simulations and digital image correlation techniques
2012 (English)In: 70th World Foundry Congress 2012, WFC 2012, 2012, , p. 396-401Conference paper, Published paper (Refereed)
Publisher
p. 396-401
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-12157 (URN)14126 (Local ID)14126 (Archive number)14126 (OAI)
Conference
70th World Foundry Congress 2012, WFC 2012, April 25-27, Monterrey, Mexico
Available from: 2016-09-13 Created: 2016-09-13 Last updated: 2018-08-21Bibliographically approved
Sjögren, T., Diaconu, V. L., Diószegi, A. & Skoglund, P. (2012). Influence of molybdenum alloying on thermomechanical fatigue life of compacted graphite irons (ed.). International Journal of Cast Metals Research, 25(5), 277-286
Open this publication in new window or tab >>Influence of molybdenum alloying on thermomechanical fatigue life of compacted graphite irons
2012 (English)In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 25, no 5, p. 277-286Article in journal (Refereed) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-6338 (URN)13947 (Local ID)13947 (Archive number)13947 (OAI)
Available from: 2016-09-08 Created: 2016-09-08 Last updated: 2018-08-21Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6657-1792

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