缺陷管道疲劳寿命预测新模型及试验验证

A new model for predicting defective pipeline fatigue-life and verification through full-scale test.

传统的韧性控制单参数疲劳寿命预测方法不适用于高韧性管线钢的疲劳寿命预测。鉴 于此,根据Paris疲劳裂纹扩展速率公式da/dN=c(ΔK)n,基于失效评估图(FAD)技术,同时 考虑疲劳裂纹扩展对裂纹尖端应力强度因子和参考应力的影响,建立了对管道疲劳寿命进行预测 的新模型,并通过自行研制的一套用于油气输送管道全尺寸实物疲劳试验系统做了验证。结果表 明:新模型计算结果为试验结果的1/2左右,从疲劳寿命预测角度是完全可接受的,具有一定的 工程安全性。

It is not practical to predict the fatigue life of materials with high toughness by using the traditional fatigue-life prediction method.In this article,a new model,using Paris fatigue crack growth expressions,da/dN=c(A△K) n,is built to predict the remained fatigue life of pipeline based on FAD(Failure Assessment Diagiam)technique.Toughness ratio and load ratio are calculated repeatedly wim every crack increment in the model.With the self-developed full-scale test system,the full.scale pipeline fatigue test was conducted to verify the applicability of this method.The results of calculation and analysis show that the calculated value by the model is about a halfofthe value obtained fromthefull-scaletest,thusthe new model is acceptable for use in the prediction of pipeline fatigue life.