Process-induced bottom defects in clinch forming: Simulation and effect on the structural integrity of single shear lap specimens. (15th September 2017)

• Record Type: Journal Article
• Authors: Coppieters, S.; Zhang, H.; Xu, F.; Vandermeiren, N.; Breda, A.; Debruyne, D.
• Is Part Of: Materials & design. Volume 130(2017)
• Page Start: 336
• Page End: 348
• Publication Date: 2017-09-15
• Subjects: Clinching -- Damage -- Process-induced defects -- Limited ductility -- Clinch forming -- Fatigue life; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2017.05.077
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Lightweight and high strength sheet metal such as aluminum alloy sheets are used in a variety of industrial applications. Due to the limited weldability of these materials, mechanical joining techniques such as clinching are of interest. The challenge in this regard is that conventional round clinch forming locally induces large plastic deformations which potentially cannot be accommodated by materials with limited ductility. Ductile damage models are used to predict the occurrence of bottom cracks during conventional round clinch forming of EN AW-6082 T6 sheet. It is shown that cracks in the bottom of a clinched joint and the final static strength of a single lap shear specimen can be numerically reproduced provided that the post-necking strain hardening behavior and damage behavior of the base material are properly identified. The observed bottom cracks did not have a detrimental effect on the static strength and fatigue life of single shear lap specimens. It is hypothesized that fatigue cracks in single shear lap tests initiate due to fretting. Graphical Abstract: Highlights: Conventional clinch forming of materials with limited ductility is investigated. The occurrence and location of process-induced defects in clinch forming can be simulated with the aid of relatively simple ductile damage criteria. The observed bottom cracks in this study have no detrimental effect on the static strength and fatigue life of clinched single shear lap specimens.