Material Characterization for FEA of the Clinching Process of Short Fiber Reinforced Thermoplastics with an Aluminum Sheet

Abstract

Multi-material and hybrid constructions are increasingly used in the automotive industry with the aim of achieving significant weight reductions of conventional car bodies, and thereby lead to effective reductions of fuel consumption. In this respect, the use of aluminum and short fiber reinforced plastics represents an interesting material combination. A full exploitation of such a material combination requires a suitable joining technique. Among different joining techniques, clinching represents one of the most appealing alternatives for automotive applications. This contribution deals with the experimental tests for determination of material behaviour of two representative materials PA6GF30 and EN AW 5754, which are used for parameterization of material models needed for numerical analysis of the clinching process using the FE software LS-DYNA. With regard to the material modeling of the aluminum sheet, an isotropic material model based on the von Mises plasticity implemented in LS-DYNA was chosen. For the description of the strain hardening behaviour of the aluminum sheet at high equivalent plastic strains, the hydraulic bulge test was carried out in addition to the uniaxial tensile test. For modeling of the short fiber reinforced thermoplastic a semi-analytical model for polymers (SAMP-1) available in LS-DYNA was taken. This material model uses an isotropic pressure dependent yield surface for the description of homogeneous materials. Finally, the FE model of clinching process is presented and an outlook of planned activities is given in terms on determination of the yield surface and hardening behaviour of PA6GF30 at high plastic strains.

Anisotropic Behaviour of Extruded Short Carbon Fibre Reinforced PEEK Under Static and Fatigue Loading

“…When considering fatigue-related aspects, the dependency of fatigue behaviour on fibre orientation has been documented in [21][22][23] for SFR-thermoplastics polymers such as PPS, PBT and PA6. Moreover, advanced constitutive models for short fibre reinforced thermoplastics were also recently proposed in [24][25][26][27]. When considering PEEK specifically, the effects of short fibre reinforcement on fatigue crack propagation were considered in [28] and [29] where an average planar fibre orientation was assumed.…”

A FEM‐based virtual test‐rig for hybrid metal‐composites clinching joints

“…The EN AW 5754 material was tested under uniaxial quasi-static tension in different direction i. e. 0°, 45°and 90°(to the rolling direction). In this re- gard, a negligible anisotropy was observed [37,38]. Accordingly, instead of the anisotropic (Hill's) plasticity model, the standard von Mises model is used.…”

The State of the Art of Finite Element Analysis in Mechanical Clinching

“…Based on this technology, hole-clinching [7][8][9], shear-clinching [10][11][12][13][14][15][16], friction-stir clinching [17][18][19][20][21], clinching-welding technology [22][23][24], and clinch-bond composite technology [25,26] have been developed and applied. The materials have been extended from carbon steel and aluminum alloy to new types of refractory materials such as high-strength steel [27][28][29][30][31][32][33], titanium alloy, and magnesium alloy, which present special advantages in the connection between a metal and a non-metal (carbon fiber and polymer [34][35][36][37][38][39][40][41][42][43][44][45][46]). The technology of connecting the double layers of the same or different materials has become mature, and the research on three layers and above is making progress.…”