一、问题的提出 在求解线弹性平面问题复合型应力强度因子时,我们绘制了理论的K_(Ⅰ,Ⅱ)C临界曲线,并经试件实测和计算分析,作出了实际的临界曲线。显然,在开展线弹性空间问题应力强度因子的研究时,同样需要绘制理论的K_(Ⅰ,Ⅱ,Ⅲ)C临界曲面。 我们采用应变能密度理论,计算和绘制了临界曲面,并将此曲面作为裂纹失稳判 I. Proposal of the problem When solving the complex stress intensity factor of the linear elastic plane problem, we draw the theoretical critical curve of K_(I, II)C. Through actual measurement and calculation analysis of the test piece, we have made an actual critical curve. Obviously, in the study of the stress intensity factor of the linear elastic space problem, it is also necessary to draw the theoretical K_(I, II, III)C critical surface. We use the strain energy density theory to calculate and draw the critical surface and use this surface as the crack instability criterion.