初始曲率对管道承载能力的影响

为研究初始曲率对管道承载能力的影响,基于梁理论建立管道横截面应变能与变形之间的数学关系式,采用三角级数法对方程进行求解,获得了管道的弯矩和椭圆度。以φ254 mm(10 in)管道为例,基于有限元仿真计算了含有初始曲率管道的弯矩、张力承载能力和椭圆度,并通过试验对弯矩和椭圆度进行比较分析。研究结果表明:随初始曲率增大,弯矩呈现先增加再减小的规律,椭圆度则一直增大;含有初始曲率的管道比没有初始曲率的管道弯矩承载能力更小、椭圆度更大;管道张力承载能力随初始曲率和弯曲段长度的增加而降低;在相同初始曲率下,管道相对弯矩的试验值和仿真值分别比理论值大约18. 9%和8. 5%,椭圆度试验值比理论值和仿真值分别小约17. 5%和9. 1%,说明理论值偏保守,但偏差在工程应用的允许范围内,验证了理论方法的正确性。研究结果可为管道安全设计提供一定的参考。

Effect of Initial Curvature on Pipeline Bearing Capacity

To study the influence of the initial curvature on the bearing capacity of the pipeline,a mathematical relationship between the strain energy and deformation of the cross section of the pipeline is established based on the beam theory. The equation is solved using the triangular series method,and the bending moment and ellipticity of the pipeline are obtained. Taking φ254 mm( 10 in) pipe for case study,the bending moment,tension bearing capacity and ellipticity of the pipe with initial curvature are calculated based on finite element simulation. The bending moment and ellipticity are compared and analyzed through experiments. The results show that as the initial curvature increases,the bending moment first increases and then decreases,and the ellipticity increases. The pipe with the initial curvature has a smaller bearing capacity and greater ellipticity than the pipe without the initial curvature. The pipe tension bearing capacity decreases with the initial curvature and the length of the bending section. At the same initial curvature,the experimental and simulated values of the relative bending moment of the pipe are about 18. 9% and 8. 5% higher than the theoretical value. The experimental value of the ellipticity is about 17. 5%and 9. 1% smaller than the theoretical and simulated values. The results indicate a conservative theoretical value,but the deviation is within the allowable range of engineering application,which verifies the correctness of the theoretical method. The study results can provide references for pipeline safety design.