考虑椭圆化和材料各向异性的管道极限弯矩承载力解析解研究

Analytical solution of ultimate bending capacity of pipeline considering ovalization and material anisotropy

已有的管道极限弯矩承载力解析方法忽略了截面的椭圆化变形,且假设管道截面达到全塑性抵抗力,这对于薄壁管道是不合理的。针对这些不足,在已有解析解的基础上,考虑管道截面塑性区的椭圆化变形以及管道轴向与环向材料的各向异性,推导了管道在内压、轴向力和弯矩联合荷载作用下的极限弯矩承载力解析解。并通过定义材料屈服后不同的广义模量,提出了管道极限弯矩承载力的上限解析解和下限解析解。在此基础上,研究了材料各向异性系数、径厚比以及初始荷载等参数对极限弯矩承载力上限和下限解析解的影响,并得到了一些有益的结论。

The previous analytic solution ignored the ovalization of the pipe cross-section,and assumed the pipe section able to attain its fully plastic capacity,which seems inappropriate for pipeline with large diameter to thickness ratio.On this basis,by considering the ovalization of the plastic region and the pipe material’s anisotropy of the axial and circumferential direction,an analytical solution of the ultimate bending capacity of pipeline subjected to combined internal pressure,axial forces and bending moments was derived in this research project.Both the lower and upper bound solutions are proposed based on the selection of a general modulus in the process of calculation.Based on the analytical solution,the effect of the anisotropy coefficient,the ratio of diameter to thickness,and the initial loading on moment capacity was studied,and some useful conclusions are obtained.