管道承压能力逆转原因探讨

比较了金属材料中短裂纹与长裂纹的扩展差异,短裂纹的扩展表现为裂纹的群体行为,短裂纹不仅会在应力作用下发生扩展,而且裂纹之间还有相互作用,相邻裂纹会在扩展的基础上发生合并,形成主导裂纹,而长裂纹的扩展表现为裂纹的个体行为.管道在制造、运输、敷设过程中产生的裂纹和缺陷是产生"承压能力逆转"的原因.用断裂力学中裂纹扩展的原理分析和研究了管道产生"承压能力逆转"的过程,并提出了相应的防范措施.

A Probe in Pipes' Pressure Reversal

There are great deference between the short cracks' and the long cracks' propagation, the short cracks' propagation are visible as the behavior of cracks in group with the action of stress, there are not only propagation of cracks, but interaction between the neighbor cracks and the combination in neighbor cracks on the basis of propagation, which results in the formation of leading cracks, but the long cracks' propagation performance as the individual behavior of crack. The cracks and defects that are caused during the process of pipe making, transportation and laying are the reason of "Pressure Reversal", and the cracks' propagation and the combination lead to pipe "Pressure Reversal". The "Pressure Reversal" is analyzed with the theory of cracks propagation of fracture mechanics and corresponding protection measures put forward.