刚性快轴向冲击圆柱壳动力屈曲的计算机模拟

用ANSYS/LS—DYNA对轴向冲击的薄壁圆柱壳的动力屈曲进行了计算机模拟。模拟中考虑了大变形效应。模拟结果表明:径厚比、约束条件、冲击速度、材料参数等对柱壳的对称和非对称动力屈曲有明显的影响。当圆柱壳一端自由一端固定时,径厚比R/h≤26,柱壳发生轴对称屈曲;反之,发生非轴对称屈曲。当圆柱壳一端夹支一端固定时,轴对称屈曲的范围增大,其径厚比R/h≤31,发生轴对称屈曲。当径厚比、约束条件、材料参数等不变时,随着冲击速度的增大,屈曲由轴对称变为非轴对称。在相同条件下,柱壳高度在一定范围内时,轴对称屈曲的范围随着圆柱壳高度的增加而变大。材料的塑性强化模量?屈服应力等对薄壁圆柱壳的动力屈曲也有明显的影响。

Computer Simulation On Dynamic Buckling Of Cylindrical Shells Under Axial Impact

Abstract In the paper, dynamic buckling of cylindrical shells under axial impact is simulated by using ANSYS/LS-DYNA and the effect of large deformation is considered. The simulation results show that the radius-to-thickness ratio, constraint condition, impact velocity and material parameters have obvious influence on the axisymmetric and unaxisymmetric dynamic buckling of cylindrical shells. The buckling mode of one end free and the other fixed is axisymmetric when the radius-to-thickness ratio is equal or less than 26, whereas it is unaxisymmetric. A scope of axisymmetric buckling of one end clamped and the other fixed is larger than that of one end free and the other fixed, axisymmetric buckling occurs when the radius-to-thickness ratio is equal or less than 31. When the radius-to-thickness ratio, constraint condition and material parameters are given, the buckling mode is from axisymmetric to unaxisymmetric as impact velocity increases. Under the same conditions, the height of cylindrical shells is a known scope, the scope of axisymmetric buckling increases as the height of cylindrical shells increases. The plastic hardening modulus and yield stress of material also influence on the dynamic buckling of cylindrical shells.