带接头管道在内压与循环载荷作用下的棘轮行为研究

液压管道在服役过程中受内压和循环弯曲载荷的共同作用．管道经常处于非比例循环加载状态，尤其是在管道接头位置处，容易产生棘轮行为，对管道的服役寿命有不利影响．因此，本文采用充液管道悬臂弯曲加载方式，对管道在接头位置处的棘轮响应进行研究。首先通过管材实验确定了材料的非线性等向/随动强化模型参数，并通过应变的实验测量结果与数值仿真结果的比较，验证了本构模型的有效性，然后建立了悬臂管道的有限元模型，模拟分析内压水平，内压小幅脉动，管道壁厚等因素对管道棘轮行为的影响．通过对带接头管道棘轮行为的研究分析，为进一步完善液压管道的设计，提高液压管道的可靠性，提供一定的理论基础．

Investigation of Ratcheting Behavior of Hydraulic Pipe with Joint under Internal Pressure and Cyclic Load

Hydraulic pipes were often subjected to the combined effect of internal pressure and cyclic bending loads during service. The consequent non-proportional cyclic loading state, especially at the location of pipe joints, was prone to ratcheting behavior and adversely affected the service life of hydraulic pipes. This paper investigated the ratcheting response of hydraulic pipe near the joint by conducting a cantilevered bending test. The parameters of the nonlinear isotropic/kinematic hardening model were determined accordingly and the efficiency of the hardening model was validated by comparing the strain data from the experiments with those from the numerical simulations. Then finite element model was constructed to analyze the effect of different factors, such as internal pressure level and pulsation, pipe wall thickness, on the ratcheting response of hydraulic pipe. The analysis on the ratcheting behavior of hydraulic pipe with joints provides a theoretical basis for further improving the design and enhancing the reliability of hydraulic pipes.