热-应力耦合场作用下含缺陷压力管道的应力强度因子研究

含有轴向长裂纹承受超高压的厚壁压力管道,当其内外壁温度不一致时会产生热应力,从而使总的应力场发生变化,裂纹尖端的应力强度因子也将发生变化。本文用有限单元法计算了由稳态热荷载和内压力共同引起的应力强度因子,并通过选取几组不同的厚壁管道几何参数、裂纹参数和温度参数,分析了它们对应力强度因子的影响规律。总结后发现,热-应力耦合场作用下,应力强度因子随径比、裂纹深度比和温度比的增加而增加,且外壁温度高于内壁时得到的应力强度因子更大,压力管道处于更加危险的工况,工程上需要特别注意。

Study on Stress Intensity Factor of Penstock with Deficiency under Heat-Stress Coupling Field

For the thick-walled penstock with long axial crack,the inconsistency of both within and outside wall temperature would generate thermal stresses,which caused the change of total stress field,as well as the stress intensity factor at the crack tip.Based on several groups of different geometric parameters,crack parameters and temperature parameters of thick-walled penstock,the stress intensity factor caused by steady state thermal load and intrinsic pressure was calculated with finite element method.Meanwhile,the effect law of abovementioned parameters on stress intensity factor was analyzed.It was indicated that under the condition of heat-stress coupling field,the stress intensity factor increased with the parameters of Ri/Ro,a/t and To/Ti.And when the temperature of outside wall was higher than that of inside,the stress intensity factor would be much higher.In that case,the working conditions of penstock were even more dangerous,which should be paid more attention.