铝合金轴心受压构件的稳定性研究与数值模拟

Stability research and numerical simulation of high-strength aluminum alloy column in compression

摘要:

为了给试验提供可靠的依据与指导,采用有限元软件ABAQUS对17根6082-T6型高强铝合金轴心受压构件进行数值模拟,并与试验结果进行对比分析.对影响有限元计算结果的各项因素,包括网格划分与尺寸、端板厚度、初弯曲大小和材料参数进行分析.有限元模型采用完全积分形式的20节点实体单元,铝合金应力应变关系采用Ramberg-Osgood模型.结果显示:采用三维实体单元C3D20进行的数值模拟与试验的屈曲荷载相对误差控制在12％以内;通常的轴向网格尺寸与端板厚度对构件稳定系数的影响可忽略不计,支座处端板的存在基本不会影响构件的铰支受力状态;稳定系数随初弯曲幅值的增大而降低,随材性参数n值的增大而提高;随着名义屈服强度f_0.2的增大,构件的屈曲荷载也随之增大,且增幅在长细比λ越小时更为显著.

Abstract:

To provide reliable verification and guidance for experiments, numerical simulations of 17 high-strength aluminum alloy columns in compression were conducted using ABAQUS and the results were compared with experimental results. Factors which influenced simulation results, including meshes size, thickness of end plates, initial imperfection and material properties were analyzed. 3D full integration continuum element C3D20 and Ramberg-Osgood model for stress-strain relationship were adopted in simulation. The simulation results show that the relative errors of buckling load between experiments and simulations are under 12％; the meshes size and thickness of end plates have a negligible influence on stability coefficient, and the existence of end plates rarely influence mechanical properties of specimens with hinge supports; as initial geometric imperfection ascends and the parameter n of aluminum alloy descends, the value of stability coefficient decreases; buckling loads of specimens obviously increases as proof stress f_0.2increases, especially for specimens with small slenderness ratio.