Surface cracks in pressure vessel is a sort of defects with quite harmfulness, so it has important significance for safety assessment of pressure vessels to calculate and study three dimension elastic - plastic J - integral and its characters.

• 压力容器表面裂纹是一种危害性较大的缺陷,计算并研究其三维弹塑性J积分值及其特性对于压力容器的安全性评介具有重要的意义。