车身弯曲刚度和扭转刚度试验研究

Experimental research on torsion stiffness and bending stiffness of vehicle body

保证车身弯曲刚度和扭转刚度是汽车设计中的一个重要环节,也是保证乘员安全的一项重要指标。目前车身静刚度的常规检验方法是将车身放置在刚度试验台上,由自动或手动加载,并通过位移传感器测量测试点的变形量,最后根据试验数据绘制车身弯曲变形曲线和扭转变形曲线。应用这一经典的静刚度检验方法,对某款轿车车身进行了弯曲刚度和扭转刚度的试验测试,为了更具体直接地诠释车身刚度的概念,根据三弯矩方程和扭转刚度计算方法,将试验数据进行了进一步的分析处理,然后将车身弯曲刚度和扭转刚度分别等效为变截面梁的刚度,最后又综合考虑弯曲刚度和扭转刚度,将车身静刚度等效为具有长方形截面的变截面梁刚度。

It is very important to make sure of the enough torsion stiffness and bending stiffness of ve- hicle body during the vehicle design procedure, and it is also a necessary performance index to the safety of drivers and passengers. Currently, the common test method for the static stiffness can be de- scribed as followed： firstly, the vehicle body is fixed on the test bench on which the vehicle body can be loaded automatically or manually ; secondly, a set of displacement sensors are set up to measure the deformation of the vehicle body under the prescribed loads; finally, the stiffness curves of torsion de- formation and bending deformation are gotten according to the experiment datum. In order to make students more easily and clearly understand the concept of the vehicle body stiffness, the experiment datum are further analyzed and calculated based on the three-moment equation and the continuum beam theory for torsion stiffness. On the one hand, the vehicle body is simulated as a beam with the variable cross-section, which bending stiffness or torsion stiffness is equal to that of the vehicle body, respectively. On the other hand, considering the torsion stiffness and bending stiffness together, the ve- hicle body is also simulated as a beam with the rectangle cross-section, which static stiffness is the same as those of the vehicle body.