弯曲载荷作用下工字形截面梁腹板中心穿透裂纹的应力强度因子

工字形梁是工程中最常见的结构之一。其中的任何裂纹都将成为结构断裂失效的隐患。带有裂纹的工字形梁是典型的三维有限边界问题，用经典方法求解其裂纹的应力强度因子通常是相当困难的。文中利用裂纹非自发扩展的能量释放率建立一个求解弯曲载荷作用下工字形截面梁中心裂纹的应力强度因子的新方法。给出工字形截面梁裂纹非自发扩展能量释放率G^＊ -积分与应力强度因子的关系，同时也给出G^＊ -积分与载荷、几何参量以及力学性能参数的关系，进而得到工字形截面梁腹板中心裂纹的应力强度因子。

STRESS INTENSITY FACTORS FOR CRACKED I BEAMS

The I beams are widely used in structural engineering. Any cracks in it may cause the structure failure. As I beam with cracks is typical three-dimensional structures, it is very difficult to determine the stress intensity factors by using classical method. In present work, an exact and very simple method to determine the stress intensity factors has been proposed based on crack surface widening energy release rate which can be expressed by the G~ * -integral and elementary strength theory of materials for slender cracked structures. From present discussions, a new and closed form of stress intensity factors is derived for I beam with center crack. The present method can also be applied to other kinds of cracked thin-walled structures.