双轴应力下含裂纹加筋曲板剩余强度的弹塑性有限元计算

AN ELASTIC PLASTIC FINITE ELEMENT ANALYSIS OF CRACKED STIFFENED CURVED PANEL UNDER BIAXIAL STRESS

采用考虑了大应变的弹塑性有限元方法,以裂纹尖端张开角为断裂准则,实现了双向受载条件下加筋曲板中裂纹起裂到失稳整个扩展过程的数值模拟计算;还对与加筋曲板有同样尺寸的加筋平板进行了分析和计算。结果表明,所提出的分析方法和所采用的断裂准则适用于对含裂纹加筋结构所进行的剩余强度分析。

An elastic plastic finite element method based on incremental theory of plasticity accounting for large strain is made for the prediction of the residual strength of crack stiffened curved panels under biaxial loading. Using the crack tip opening angle (CTOA) as the fracture criterion controlling stable crack extension, the entire process from the initiation of crack growth up to the instability of crack extention is simulated, the residual strength and crack tolerance are presented and some complex mechanics phenomena are found.The results show that the analytic method presented and the fracture criterion adopted are suitable for the residual strength prediction of cracked stiffened structure, the increasing curvature of the cracked stiffened curved panel can change remarkably the stress, strain and displacement field around crack tip and will reduce considerably the loading capability of the cracked stiffened structure.