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本文根据带内外壁人工缺口高压聚乙烯反应管的内压疲劳试验结果,分析了适用于厚壁管的应力强度因子表达式,研究了残余应力衰减对反应管疲劳裂纹扩展寿命的影响。研究结果表明:厚壁管的疲劳裂纹扩展计算应采用Newman—Raju公式(对外壁裂纹还应进行适当修正);自增强残余应力的作用主要在提高裂纹萌生寿命,而对在役反应管的裂纹扩展寿命影响不大;反应管的裂纹扩展寿命较短,所以应尽量避免内外壁产生裂纹。
In this paper, according to the results of internal pressure fatigue test of high pressure polyethylene reaction tube with internal and external artificial notch, the stress intensity factor expression suitable for thick-walled tube is analyzed and the effect of residual stress attenuation on the fatigue crack growth life of the reaction tube is studied. The results show that the Newman-Raju formula should be used to calculate the fatigue crack growth of the thick-walled tube (the outer wall cracks should be properly corrected); the effect of self-reinforced residual stress is mainly to improve the crack initiation life, while the cracking of the in-service reaction tube Extended life has little effect; reaction tube crack propagation life is shorter, so should try to avoid cracks in the outer wall.