Analysis of Failure Assessment Curves for Pipe Girth Welds
In order to improve the accuracy of the pipeline fracture assessment,the FAL prediction model is set up under three typical conditions based on the theory of the elasto-plastic fracture mechanics combined with the numerical simulation and the emulation methods.The effects of the material properties,crack geometry,and load type(tensile,internal pressure and bending)on the FAL were considered separately.The results of the study show that the pipe,the wall thickness and the outer diameter have a little effect on the failure assessment curve,which can be basically neglected.When a/t<0.5,the FAL in the elasto-plastic zone distribution is more concentrated;when a/t≥0.5,the FAL will have a high sensitivity with the change of crack length.At the same time,a multi-parameter fitting model is proposed to simplify the complex process of existing three-stage fracture evaluation,in which the multi-parameter fitting model material yield strength,tensile strength,crack depth,crack length and pipe wall thickness,and the prediction results show that the multi-parameter model can describe the changing trend of complex fracture evaluation curve.
万方数据
维普
