重复冲击下含裂纹加筋板结构失效模式分析

Failure Mode Analysis of Stiffened Plates with Initial Cracks under Repeated Impacts

开展了含裂纹加筋板重复冲击试验,探究不同裂纹长度和位置对含裂纹加筋板失效模式的影响,并结合数值模拟对失效模式进行分析。结果表明,裂纹通过改变加筋板塑性区域的分布影响结构吸能,使含裂纹加筋板在重复冲击作用下的失效模式产生差异。在一定的冲击能量下,含裂纹加筋板的失效模式不仅表现为整体性的塑性大变形失效,而且可能伴随局部或者整体构件的断裂失效。当裂纹位于外板时,裂尖张开距离随加筋板中心塑性变形的累积而线性增加,增长速率与裂纹长度呈正相关,裂尖张开可导致局部发生小范围断裂;位于加强筋自由边的裂纹随冲击次数增加逐渐扩展,直至加强筋完全断裂。研究结果可为工程结构抗冲击安全性设计提供参考。

Repeated impact tests of stiffened plates with initial cracks were carried out and effects of the crack length and location on the failure mode were investigated.Combined with numerical simulation,failure modes of stiffened plates with initial cracks were analyzed.The results show that the cracks make a difference in the failure modes of the stiffened plates by altering the distribution of its plastic region and thus affecting the absorption of the structural energy.Under certain impact energy,the failure mode of the plate is not only manifested as global large plastic deformation but also accompanied by local or entire component fracture.When the initial crack is located in the outer plate,the crack tip opening distance increases linearly with the accumulation of plastic deformation in the center of the stiffened plate,and the increase rate is positively correlated with the crack length.The crack tip opening can lead to the occurrence of local small-scale fracture.When the initial crack is located in the free edge of the stiffener,the crack gradually expands with repeated impacts until the stiffener completely fractures.The research results can provide a reference for the design of impact safety for engineering structurers.