摘要
The approach combining the dynamic caustics method with high-speed photography technology is used to study the interaction between propagating cracks and three kinds of deformity inclusions（ cylinder inclusion, quadruple inclusion and triangular inclusion） under lowvelocity impact loading. By recording the caustic spots of crack tips at different moments during the crack propagation, the variation regulations of dynamic stress intensity factors（ DSIF） and crack growth velocity with respect to time are obtained. The experimental results showthat the resistance effects to crack growth are varied with different shapes of inclusions in specimens, and the quadruple inclusion＇s effect is more apparent. The distortion degree of caustic spots is affected by the shapes of inclusions as well, and the situation is more serious for cylinder and quadruple inclusions. The overall values of DSIFs of triangular inclusion specimen are greater than the others, and the crack growth velocities, characteristic sizes and DSIFs showprocesses of fluctuations because of the disturbance of reflection waves in specimens. The results provide an experimental basis for the analysis of strength and impact-resistance ability in structures with deformity inclusions.
将动态焦散线方法与高速摄影技术相结合,研究了低速冲击载荷作用下3种异型夹杂(方形夹杂、圆形夹杂和三角形夹杂)与基体裂纹的相互作用.通过记录不同夹杂情况下裂纹尖端自起裂到贯穿的动态焦散斑图,分析了Ⅰ型裂纹的动态应力强度因子KdΙ和裂纹扩展速率v与时间的关系.实验结果表明:不同形状的夹杂会对裂纹尖端产生不同的阻裂效果,其中方形夹杂阻裂效果最明显;裂纹尖端焦散斑的畸变程度受到试件中夹杂形状的影响,圆形和方形夹杂对裂尖焦散斑畸变影响程度较大;三角形夹杂试件在裂纹扩展过程中裂尖动态应力强度因子值普遍高于圆形与方形夹杂试件,3组试件在断裂过程中裂尖由于受到反射波的扰动,其扩展速度、特征尺寸和动态应力强度因子值均呈现一定的波动性.研究结果为含异型夹杂构件的强度设计及抗冲击性能评估提供了依据.
基金
The National Natural Science Foundation of China(No.51374210,51134025)
the 111 Project(No.B14006)
