材料应变率对圆柱壳轴向冲击屈曲的影响

THE EFFECTS OF STRAIN-RATE-SENSITIVITY ON DYNAMIC BUCKLING OF CYLINDRICAL SHELLS UNDER AXIAL IMPACT

研究了轴向冲击载荷作用下材料应变率对圆柱壳弹塑性冲击屈曲的影响 ,采用Karman_Donnell运动方程 ,本构关系采用增量理论 ,联立Cowper_Symonds关系 ,求得相应的动屈服应力 ,借助增量数值计算方法求解运动方程 ,计算表明 :材料的应变率敏感性显著地提高了结构的抗冲击屈曲能力 ;基于B_R准则的屈曲判断方法和采用Southwell方法可以获得一致的临界屈曲载荷。

The effects of strain-rate-sensitivity on dynamic buckling of cylindrical shells under time-dependent axial impulsive loads are discussed.The time-dependent displacements of cylindrical shell are assumed to be governed by nonlinear equation of motion based on the Karman-Donnell kinetic relations.The increment theory is adopted to form the constitutive relation of material and the dynamic yield stress is calculated from Copwer-Symonds relation.The increment numerical method is used to solve the kinetic equations.The results exhibit that the critical buckling loads are improved greatly while considering the material strain rate sensitivity,and dynamic buckling loads are estimated based upon the notion of a Southwell plot conforming to the corresponding data of the B-R criterion