PSI - Issue 23

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Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000 – 000 Structural Integrity Procedia 00 (2019) 000 – 000

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Procedia Structural Integrity 23 (2019) 463–468

9th International Conference on Materials Structure and Micromechanics of Fracture Determination of crack initiation in an interior cold-weld by combining reverse engineering and digital image correlation analysis C. Skotarek a , K. Markstaedter b , A. Brueckner-Foit a* , A. Rienaecker b 9th International Conference on Materials Structure and Micromechanics of Fracture Determination of crack initiation in an interior cold-weld by combining reverse engineering and digital image correlation analysis C. Skotarek a , K. Markstaedter b , A. Brueckner-Foit a* , A. Rienaecker b

a Institute for Materials Engineering, D-34109 Kassel, Germany b Institute for Drive Systems and Vehicle Technology, D-34109 Kassel, Germany a Institute for Materi ls Engine ring, D-34109 Kassel, Germany b Institute for Drive Systems and Vehicle Technology, D-34109 Kassel, Germany

Abstract Abstract

© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers © 201 9 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. Micro-electronic devi es very often contain joints which are v tal for operati , but are no longer accessible after assembly. This s especially true for cold welds, as they a e formed by applying a certain contact pressure. Isolating the joint by cu ting would inevitably relax this contact pr ssure and seriously disturb r ven destroy the joi t. A solution t this problem is pr sented in terms of multi-st p reverse engineering approa h. First, the g ometries of the components in question are precisely determined by CT analysis. Then the ynamic assembly process is simulated, and the spatial distributi n of contact str ss s is derived. A c hesive zone model is introduce which epresent the cold-weld zone. Then the assembled component is subjected to mechanic l loading, and its deformati n field is determined using digital image correlation. Monito points susceptible to e onset of damage can b det rmined from t simul ti n model, an their deformation is recorded during the tests. It is shown that this procedure gives reliable estimates of the critical loads required for crack initiation. © 201 9 The Authors. Published by Elsevier B.V. This is an ope acces article under the CC BY-NC-ND lic nse (http://creativecommon org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. Micro-electronic devices very often contain joints which are vital for operation, but are no longer accessible after assembly. This is especially true for cold welds, as they are formed by applying a certain contact pressure. Isolating the joint by cutting would inevitably relax this contact pressure and seriously disturb or even destroy the joint. A solution to this problem is presented in terms of a multi-step reverse engineering approach. First, the geometries of the components in question are precisely determined by CT analysis. Then the dynamic assembly process is simulated, and the spatial distribution of contact stresses is derived. A cohesive zone model is introduced which represents the cold-weld zone. Then the assembled component is subjected to mechanical loading, and its deformation field is determined using digital image correlation. Monitoring points susceptible to the onset of damage can be determined from the simulation model, and their deformation is recorded during the tests. It is shown that this procedure gives reliable estimates of the critical loads required for crack initiation.

Keywords: Press-fit connector; digital image analysis; cohesive zone; cold welding Keywords: Press-fit connector; digital image analysis; cohesive zone; cold welding

* *Corresponding author. Tel.: +49-561-804-3680; fax: 49-561-804-3650 E-mail address: a.brueckner-foit@uni-kassel.de * *Corresponding author. Tel.: +49-561-804-3680; fax: 49-561-804-3650 E-mail address: a.brueckner-foit@uni-kassel.de

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the IC MSMF organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an ope acces article under CC BY-NC-ND lic nse (http://creativecommon org/licenses/by-nc-nd/4.0/)

Peer-review under responsibility of the scientific committee of the IC MSMF organizers.

2452-3216 © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ICMSMF organizers 10.1016/j.prostr.2020.01.130