压力容器内外壁轴向双裂纹相互作用

压力容器在制造过程、疲劳与复杂应力状态下会产生裂纹,这些裂纹的存在将影响到容器的安全使用,有必要对容器内外壁同时存在轴向双内外裂纹相互作用对应力强度因子的影响进行深入研究。利用ANSYS、FRANC 3D有限元软件建立含内外壁轴向裂纹的柱形压力容器模型,分析不同裂纹深长比的内外裂纹在静、动态下的相互作用对应力强度因子的影响,拟合得到不同裂纹深长比下名义应力强度因子的变化曲线,发现裂纹相互作用对深长比小的初始裂纹的扩展有促进作用,而对深长比大的初始裂纹的扩展则有抑制作用。研究结果对于不同深长比多裂纹相互作用下的裂纹扩展机理及多裂纹断裂失效评定问题的研究具有借鉴作用。

The interaction between axial double cracks in the inner and outer walls of pressure vessels

Cracks are usually generated when a pressure vessel is being manufactured or in the states of fatigue and complex stress,and the existence of these cracks impacts the safe operation of these vessels.In this paper,the influence of the interaction between the axial double inner and outer cracks in the inner and outer walls of the pressure vessel on the stress intensity factor were studied deeply.Firstly,the cylindrical pressure vessel model with axial cracks in the inner and outer walls was established by finite element software FRANC 3D and ANSYS.Then,the influence of the interaction between the inner and outer cracks with different depth-to-length ratios under static and dynamic conditions on the stress intensity factors was analyzed.Finally,the variation curve of the nominal stress intensity factor for different crack depth-to-length ratios was obtained by means of fitting.It is indicated that the interaction between cracks promotes the propagation of the cracks with low depth-to-length ratio,but inhibits that of initial cracks with high depth-to-length ratio.The research results can be used as the reference for studying the propagation mechanisms under the interaction of multiple cracks with different depth-tolength ratios and evaluating multi-crack fracture failure.