超高压管式反应器端部结构应力场的研究

Study on Stress Field of End Structure of Ultrahigh Pressure Tubular Reactor

超高压管式反应器是管式超高压聚乙烯装置的关键设备,其端部通常为夹套与反应管的过盈配合连接结构。利用电阻应变测量技术,针对某石化厂发生疲劳断裂的超高压管式反应器端部结构应力场开展试验研究,采用应力释放法获得过盈配合后的局部应力场数据,在此基础上,建立基于ANSYS软件的有限元模型,并与试验数据进行对比分析。结果表明,端部结构的过盈配合边缘局部范围内存在较高的轴向拉应力,且大于环向应力,应力水平随过盈量增加而提高;接触刚度对应力场数值模拟结果影响较大,在保证收敛的前提下应尽量增大接触刚度以提高模拟精度,有限元模拟结果与试验数据符合得较好。研究结果对后期的数值模拟以及结构失效原因的分析提供重要参考依据。

Ultrahigh pressure tubular reactor is the key equipment of tube-type ultrahigh pressure polyethylene, its end is usually the shrink-fit structure composed of jacket and reaction tube. Stress field of end structure of the ultrahigh pressure polyethylene tubular reactor, in which fatigue fracture occurred, is experimentally studied by measuring electric resistance Strain. And the local stress field after shrink-fit is obtained based on stress release method. In terms of experimental results, ANSYS FEM is built and the simulation results compared with experimental data. The results show that a large tensile axial stress appeared on the location at the edge of the shrink-fit and it＇s larger than hoop stress, and the local stress level increases with the increase of shrink-fit range; the influence of contact stiffness on simulation results is significant, and in order to improve the simulation accuracy, the combination of contact stiffness and convergence has to be optimized; the FEM simulation results is consistent well with the experimental data. The study results can provide some insight into subsequent numerical simulation and failure analysis of the end structure.