【摘要】 本文基于钝裂纹端部位移场的渐近解和等参元构造方法,开发了一种新的适合钝裂纹端部应力场计算的扩展单元法,为了消除不同单元间的位移不协调又在扩展单元的基础上提出过渡单元。和常规的等参元相比,扩展单元除了以节点位移为待求未知量外,它们额外增加了Ⅰ型和Ⅱ型广义应力强度因子作为未知量。根据这个理论我们编制了有限元的程序并计算了算例,算例表明,在网格较大的情况下,与常规等参元计算方案相比,扩展单元和过渡单元法更好地接近理论值,它具有计算精度高、减少缺陷附近的单元数量和计算时间等优点。更多还原

【Abstract】 Based on the asymptotic solution near a blunt crack end,some enriched elements were intro- duced for computing the stress fields near the blunt crack end.In order to eliminate the displacement dis- crepancy between enriched elements and isoparametric elements,some transitional elements were also in- troduced.In the enriched element and transitional element,two generalized stress intensity factors were combined to the node displacements as unknows and the corresponding code was developed.The calculated results show that the enriched and transitional element schemes are better than that of the isoparametric element,especially in the case of coarse meshes.更多还原