Abstract: To investigate the influence of force-based and stress-based spot weld modeling methods on cab fatigue behavior, a heavy-duty truck cab is selected as the research object. A rigid-flexible coupled virtual model of the cab is developed in ADAMS, and road load spectrum data are collected from vehicle proving ground tests. The virtual iteration method is applied to reproduce the cab,s load-bearing state under test conditions. Simulation results are correlated with experimental data to validate the accuracy of the virtual test rig model, while dynamic fatigue load spectra at cab interface points are extracted for subsequent analysis. Using the quasi-static method with the decomposed load spectra as input, the accuracy of the force-based and stress-based methods in predicting spot weld fatigue is evaluated. Results indicate that both approaches yield consistent fatigue damage distributions in the cab. However, the stress-based method demonstrates higher accuracy, with simulation outcomes aligning more closely with bench test data, whereas the force-based method offers advantages in modeling efficiency and computational speed. Finally, process improvements are applied to critical weld regions, leading to a 5.89-fold increase in cab fatigue life, thereby verifying the effectiveness of the proposed modifications.

Key words: virtual iteration; load spectrum acquisition; spot weld fatigue; multibody dynamics

摘要： 为探究力法与应力法两种焊点建模方法对驾驶室疲劳的影响规律，以某重卡驾驶室作 为研究对象，在 ADAMS 中搭建重卡驾驶室刚柔耦合虚拟模型，并采集汽车试验场道路载荷 谱数据，采用虚拟迭代法复现驾驶室在试验场的承载状态，输出仿真数据与试验数据进行对 标，验证虚拟台架模型的精度，同时分解出驾驶室接口点动态疲劳仿真载荷谱数据。采用准 静态法，以分解的载荷谱数据为输入，研究力法与应力法应用驾驶室焊点疲劳仿真的精度， 结果表明两种方法下的驾驶室损伤分布基本一致，应力法精度较高，仿真结果与台架试验结 果更为接近，而力法的建模效率高，运算速度快。最后，对驾驶室焊点危险部位进行工艺改 进，改进后的驾驶室寿命提高 5.89 倍，证明了改进方式的有效性。

关键词: 虚拟迭代；载荷谱采集；焊点疲劳；多体动力学