Abstract

Resistance Rivet Spot Welding (RRSW) is a joining technique with high flexibility and cost efficiency for connecting steel and aluminum sheet metal parts in an automotive body in white (BIW). Using this method, both pure steel and steel–aluminum mixed BIW can be produced in the same assembly line. The prediction of the load-bearing capacity and failure behavior in crashworthiness calculation by the OEMs requires a stable finite element (FE) simulation model for both static and dynamic load cases. In this paper, an experimental and numerical study on the behavior of RRSW connections is presented. After the analysis of different material models with varying FE codes, the material model MAT 100DA of LS-DYNA was chosen as the starting point for crash simulation. For the determination of the model parameters as well as the entire FE model, material tests with different strain rates and KS-II-tests with three different velocities were performed. The FEM parameters were determined via iterative parameter calibration. Lap shear, peeling, and component tests were conducted for parameter validation along with the FE calculations. In the experiment, the loading rate-dependent behavior of the RRSW joining was observed in terms of force-displacement curves and the failure phenomenon. The simulation’s results show that the performance of vehicle components joined by RRSW are predicable by using the material model MAT_100DA. The prediction of failure behavior can be further improved by using a detailed meso-scale model.

摘要

电阻铆钉点焊 (RRSW) 是一种具有高灵活性和成本效益的连接技术，用于连接白色汽车车身 (BIW) 中的钢和铝钣金零件。使用这种方法，可以在同一条流水线上生产纯钢和钢铝混合白车身。OEM 在耐撞性计算中对承载能力和失效行为的预测需要针对静态和动态载荷情况的稳定有限元 (FE) 仿真模型。在本文中，提出了关于 RRSW 连接行为的实验和数值研究。在分析了具有不同 FE 代码的不同材料模型后，选择了 LS-DYNA 的材料模型 MAT 100DA 作为碰撞模拟的起点。对于模型参数以及整个有限元模型的确定，进行了不同应变率的材料测试和三种不同速度的 KS-II 测试。确定 FEM 参数通过迭代参数校准。进行了搭接剪切、剥离和组件测试以进行参数验证以及 FE 计算。在实验中，从力-位移曲线和破坏现象的角度观察了 RRSW 连接的加载速率相关行为。仿真结果表明，使用材料模型MAT_100DA可以预测RRSW连接的车辆部件的性能。通过使用详细的中尺度模型，可以进一步改进对失效行为的预测。