复杂薄壁箱形结构强度数值模拟及试验验证

NUMERICAL SIMULATION AND EXPERIMENTAL VALIDATION ON COMPLEX THIN-WALLED STRUCTURES UNDER INTERNAL PRESSURE LOAD

对复杂薄壁箱形结构在内压载荷下的力学响应和承载能力进行数值分析。得到箱体在内压载荷下的应力和位移变化特性,箱体各模压板块中与加强槽毗邻的球冠边缘区域的Mists等效应力始终占控制地位;获取箱体的屈曲失效模式,基准模型箱体底板的屈曲临界载荷为80 kPa。对模型箱体力学响应特性和承载能力进行试验验证,试验数据与数值模拟结果较为一致,控制点应力最大偏差为12．6％,位移偏差最大值为10．9％;另外,试验发现这种薄壁结构存在底部模压板失稳、包角渗漏和斜拉筋拉脱等3种失效模式。

The mechanical response of a complex thin-walled rectangular structure subjected internal pressure load is investigated numerically based on finite element analysis （FEA） code MSC. Marc/Patran, and the nonlinearities of the material and geometry are both taken into account. The characteristics of deformation and the properties of stress distribution of this kind of structure are obtained, where the largest Mises equivalent stress are found to be located at the region between the reinforcement channels and the convex face in the molded units. And the critical buckling load of bottom molded-units of the reference model structure is found to be 80 kPa. The numerical model is validated experimentally with a real assembled thin-walled water tank. It is found that numerical predicated displacements as well as the stress of control points are in reasonable agreement with the experimental data. In the experiment, the failure modes of the structures are found to be buckling of bottom molded units, leaking at the comer of the molded units and fracture of stiffeners. Based on this numerical model, parameters such as the height as well as the diameter of the convex face, the position of the reinforcement channels and the arrangement of stiffeners, an optimum shape of molded unit is optimized, and the load-carrying capability of the structure is enhanced.