商用车白车身焊点模拟对模态分析的影响研究

Study on effect of spot weld modeling on modal analysis of a commercial vehicle's body-in-white cab

针对商用车驾驶室有限元模态分析中如何选择点焊模拟方式来建立有限元模型这一问题,以某重型商用车驾驶室白车身为研究对象,分析了RBE2、CWELD和ACM等几种典型的焊点模拟方式对其模态分析的影响。首先,阐述有限元分析中3种焊点模拟的典型方法,并较详细地说明3种焊点模拟方法的特点,以此为基础建立某型商用车驾驶室白车身有限元模型并进行模态分析,得到该白车身驾驶室的模态特征,再利用DHDAS动态信号采集分析系统,采用单点激励法对该驾驶室白车身进行模态试验及模态参数识别,并通过对比分析讨论了3种焊点模拟方式的精度。结果表明,柔性单元模拟焊点比刚性单元模拟更为准确,CWELD和ACM两种柔性单元模拟结果误差在2.5%以内,具有等效模型精度。引用误差函数验证了CWELD单元模拟焊点的有限元模型的可靠性。研究结果可为有效提高商用车驾驶室有限元建模质量提供了焊点模拟方式的选择参考。

The effect of spot weld modeling on modal analysis was investigated for the finite element modal analysis of commercial vehicle cab by applying typical spot weld modeling methods（ RBE2、CDELD,ACD） based on a commercial vehicle＇s body-in-white cab. Firstly,the characteristics of three typical methods of spot weld simulation methods in finite element analysis were described in detail. Based on this,the finite element model of the cab was built and the modal characteristics of the body-in-white cab were obtained. Furthermore,single point excitation method was adopted to test for for modal analysis and modal parameter identification of the body-in-white cab by using DHDAS dynamic signal acquisition and analysis system. By comparative analysis,the accuracy of threetypical spot weld simulation methods was discussed. The results show that the flexible element spot weld modeling is more accurate than rigid element spot weld modeling. Meanwhile,the two flexible spot modeling elements CWELD and ACM have the equivalent model precision with the error of the simulation less than 2. 5%. Finally, the viability of using CWELD in spot weld modeling is confirmed by the application of error function. These results provide options of spot weld modeling for improving the finite element modeling quality of Commercial vehicle cab effectively.