Construction Procedure of Spot Weld Failure Model for Crash Simulation
This paper proposed the construction methodology of spot weld failure model for a crash simulation based on the experiments and the simulations which is called a hybrid method. The test procedure was designed to obtain the failure load of a spot weld unde
- PDF / 779,029 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 31 Downloads / 237 Views
Construction Procedure of Spot Weld Failure Model for Crash Simulation J. Ha, J.-H. Lim, and C.-Y. Oh Abstract This paper proposed the construction methodology of spot weld failure model for a crash simulation based on the experiments and the simulations which is called a hybrid method. The test procedure was designed to obtain the failure load of a spot weld under combined loading conditions. The failure surface is determined based on bending moment, normal force and shear force. Those components acting on the spot welded part are obtained from finite element analysis results, which are defined by the real experimental conditions. The proposed failure surface was constructed based on Wung [Wung, Exp Mech 41, 107–113, 2001; Wung et al., Exp Mech 41, 100–106, 2001] model except torsion term. It was found that the failure surface of mild steel was expressed as a function of previous researches, however failure surface of high strength steels and advanced high strength steels were different shape from previous research results. The proposed failure criterion is wellestimated for specimen levels such as cross tension, loading angle of 30 , loading angle of 45 , coach-peel and lap-shear tests. Keywords Spot weld • Failure model • Hybrid method • Prediction equation • Crash simulation
9.1
Introduction
Improvement of crashworthiness becomes one of the challenging issues in auto industries together with the light weight design. Actual crash test cost to evaluate the crashworthiness of the auto-body structure become larger due to tighten regulation for a car crash. Thus, computer simulation as an alternative method to evaluate the crashworthiness of the autobody structure is widely used in the automotive industry [3]. In order to estimate the crashworthiness properly, the correct failure prediction of a spot weld is indispensable for the crash simulation [4, 5]. Rupture of a spot weld is likely to occur prior to failure of the base metal when a large load is applied to the auto-body structure since extremely high stress is concentrated at the interface between the nugget and the base metal [6]. Because the impact load transferred from one part to another part through a spot weld is abruptly changed after the spot weld fails, deformation behaviors of the auto-body structure usually reveal large discrepancies between experiment and simulation after joined components are separated. Research on the failure characteristics of a spot weld has been investigated over the past few decades. Especially, it is necessary to estimate the strength of spot welds under various loading modes in order to provide a failure criterion of a spot weld for the structural analysis or crashworthiness assessment of the auto-body structures using the finite element analysis. Lee et al. [7], Barkey and Kang [8], Madasamy et al. [9] and Langrand and Combescure [10] proposed testing fixtures to provide various loading conditions including pure axial, mixed axial/shear, or pure shear loads on a spot-welded specimen through changing the position of the
Data Loading...
