含环向穿透裂纹正交各向异性TA2管道的失效评定曲线（英文）

Failure Assessment Curve of Orthotropic TA2 Pipe with Circumferential Through-wall Crack

运用三维有限元弹塑性分析计算了含环向穿透裂纹各向同性和正交各向异性TA2管道的极限载荷,J积分以及失效评定曲线。研究了不同几何尺寸和不同裂纹尺寸的管道以及正交各向异性对失效评定曲线的影响。结果表明:正交各向异性管道与各向同性管道的极限载荷,J积分有明显差异。如果将正交各向异性材料视作各向同性,当内压与极限载荷比L_r<0.9时,评定结果会比较保守,相反当L_r>0.9时,评定结果会有一定的危险。对正交各向异性材料而言管道轴向力学性能强于环向时比较危险。因此对含环向穿透裂纹管道进行失效评定时,材料正交各向异性的影响不能忽略。

The limit loads, J integral results and failure assessment curve(FAC) of the circumferential through-wall cracked isotropic and orthotropic pipes of pure titanium TA2 were calculated based on the 3-dimensional(3-D) elastic-plastic finite element(FE) analyses. The effects of pipe geometry, crack size and orthotropy on the FAC were investigated. Calculation results show that the limit load and J integral of the isotropic pipe and the anisotropic pipe are obviously different. For the failure assessment curves, when the load ratio Lr<0.9, if the orthotropic material is evaluated as an isotropic material, the evaluation result is conservative. On the contrary, when the load ratio Lr>0.9 and if the orthotropic material is evaluated as an isotropic material, the evaluation result is somewhat dangerous. And it is most dangerous when the mechanical properties of the orthotropic material in axial direction are stronger than in circumferential direction. Thus the orthotropy of circumferential through-wall crack pipe cannot be neglected for defect assessment.