温度对车身钢铝胶铆连接结构热应力变化的影响

Influence on thermal stress of autobody steel-aluminum clinchadhesive connection structure

针对车身结构在涂装过程中温度变化对钢铝胶铆连接结构的影响,研究了影响结构热应力的主要因素。在钢、铝、粘接剂的单向拉伸试验和热膨胀试验基础上进行钢铝胶铆连接结构高温热膨胀试验,获得了钢板、铝板表面的应变值。建立了钢铝胶铆连接结构热膨胀有限元仿真模型,通过试验验证了仿真模型的有效性。分析胶铆结构在升温、保温、降温过程中的应力变化情况,获得了钢铝胶铆连接结构在厚度方向上尺寸随温度的变化规律。研究了粘接剂厚度、粘接宽度和金属铆接顺序对钢铝胶铆连接结构在高温作用下的影响。结果表明,钢铝胶铆连接结构在经历高温作用后会产生残余应力和热变形;适当增大粘接剂厚度可以降低胶铆连接结构的残余应力和应力集中,降低结构整体的热变形;增大粘接宽度能有效降低胶铆接头中的残余应力,但会导致钢铝胶铆连接结构塑性变形增大;铝板在上、钢板在下铆接时胶铆接头的残余应力较小。

In view of the influence of temperature change on steel-aluminum clinch-adhesive connection structure during the coating process,the main factors influencing the thermal stress were studied.The high temperature thermal expansion tests were carried out based on the tensile tests and thermal expansion tests of steel,aluminum and adhesive,and the strain value was obtained.The finite element simulation model of thermal expansion of steel-aluminum clinch-adhesive connection structure was established,which was verified by experiments.The stress changes of the joints and the bonding part in the process of heating,heat preservation and cooling were analyzed,and the variation of the overall size of the steel-aluminum clinch adhesive connection structure with temperature in the thickness direction was obtained.The effects of adhesive thickness,bonding width and riveting sequence of metals on the properties of steel-aluminum clinch-adhesive connection structure were studied.The results show that the residual thermal stress and thermal deformation of the structure occur after high temperature.Residual thermal stress and stress concentration and thermal deformation of the whole structure can be reduced by properly increasing the thickness of the adhesive.Increasing the proportion of adhesive width can effectively reduce the residual stress in the joint,but it leads to the increase of plastic deformation in the steel-aluminum clinch-adhesive connection structure.The residual thermal stress of clinch-adhesive joint is smaller when aluminum plate is riveted at the top to steel plate.