Abstract:  Aiming at the problem that the cracks on the inner wall of the thick-walled tube structure have an important influence on the strength and safe use during the service process, the mutual influence law of the parallel biaxial cracks on the inner surface of the thick-walled tube was studied. An interaction impact factor λ was defined based on analysis of theoretical formula of stress intensity factor of thick wall pipe single axial crack. According to finite element method, stress intensity factors of double axial surface cracks in thick-walled cylinders were calculated in different situation of angles, ratio of crack length to wall thickness and ratio of our diameter to wall thickness. The variations of different influencing factors on the interaction between parallel biaxial cracks on the inner surface of thick-walled cylinder and the stress intensity factor at the crack tip were analyzed through the calculation results. The results indicate that there is a critical angle determining the closure and opening effect between the biaxial cracks. When the angles between biaxial cracks are larger than the critical value, the opening effect can be strengthened with the increase of angles value, ratio of crack length to wall thickness and ratio of our diameter to wall thickness, and vice versa.

Key words: thick-walled pipe; stress intensity factor; biaxial cracks; interaction impact factor

QIN Yuan-yuan, QIN Xiao-feng, CHEN Zhan-chun. Factors influence on the interference of parallel biaxial cracks in inner surface of thick-walled pipe［J］.Journal of Mechanical & Electrical Engineering, 2022,39(2):276-280.