基于壳单元的侧碰移动可变形壁障研究

Research on Moving Deformable Barrier Model Based on Shell Element

采用壳单元技术,参照蜂窝铝的真实窝孔结构,建立基于壳单元的侧碰移动可变形壁障(Moving deformable barrier,MDB)有限元模型;针对1∶1尺寸建模导致模型规模过大的问题,进行窝孔及单元尺寸等比例扩大,将单元规模缩减到原来的1/5;应用静态异面压缩仿真,对单元厚度与压缩强度进行参数化研究,合理匹配窝孔及单元尺寸扩大之后的单元厚度,确保模型缩放前后的静态压缩力学性能达到一致;针对动态试验压缩强度大于静态试验的现象,采用简易气囊模拟MDB窝孔中空气受压缩的率效应;结合侧碰试验中的蜂窝铝失效现象,设置铝箔的材料失效以及铝箔、前面板之间粘胶的材料失效;对所建立的壳单元MDB模型进行零部件级别与整车级别的试验验证,结果表明壳单元MDB模型具有很高的精度。

A finite element model of moving deformable barrier（MDB） based on shell element is built by applying the shell element technology according to real structure of the honeycomb.For the situation of huge number of elements caused by shell element modeling as the same size of physics state,cell size and element size is enlarged by the identical scale,which reduce the number of elements significantly.The out-of-plane compression simulation is executed to obtain the relationship between the thickness of shell elements comprising a honeycomb and compressive strength,a parameter study using a test piece is performed to achieve the compressive strength of the actual part.The air pressure effect is obtained from with the results of punch tests by subtracting static punch test result from dynamic punch test result.Material failure is applied to simulate the failure phenomena of aluminum foil and the glue between the foil and the cover board during the crash.The MDB model based on shell element shows high precision when the analysis results are compared to the results of a component crush test and a side impact test.