扶梯上侧板横撑液力成形仿真研究

目的 缩短上侧板横撑胀形件的开发周期，降低开发成本。方法 采用理论研究与仿真分析相结合的方法对胀形管件的壁厚分布及加载路径进行研究。首先，借助ABAQUS有限元软件，对简单管件两次液压成形过程进行仿真模拟，通过对比仿真结果与实验结果，验证仿真建模的正确性。其次，基于有限元软件对横撑管件液力成形、退火等过程进行仿真分析。最后，通过分析、总结获取合理的加载路径。结果 通过理论计算得到了预胀形所需的内压力值，为横撑管件预胀形仿真分析提供了参考。在预胀形阶段，当内压力<65 MPa时，由于内压力不足，管件无法成功胀形，当内压力>65 MPa时，管件中间胀形区域存在应力集中现象，不利于后续管件胀形，所以预胀形阶段的合理加载路径为常压65 MPa。在终胀形阶段，常压加载路径下的胀形结果不理想，而在多线性加载路径4下退火件及未退火件都能获得理想的胀形结果，因此，多线性加载路径4为终胀形的合理加载路径。结论 相较于常压加载，终胀形阶段采用多线性高压加载，管件成形效果更好;终胀形前进行退火处理，可以降低胀形管件的残余应力，壁厚分布也更加均匀。

Simulation Study on Hydraulic Bulging Process of Lateral Brace for Escalator Upper Side-panel

The work aims to shorten the development cycle of bulging part of lateral brace for upper side-panel and reduce the developmental cost. Theoretical research and simulation analysis were combined to study the wall thickness distribution and loading paths of bulging tube. Twice bulging processes of simple shape tube were simulated by ABAQUS finite element software firstly, simulation results were compared with the experimental results and the correctness of simulation modeling was verified, and then the hydraulic bulging and annealing processes of lateral brace tube were numerically simulated based on finite element software and finally the reasonable load paths were obtained through analysis and summary. The internal pressure required for pre-forming was obtained through theoretical calculation, which provided a reference for pre-forming simulation analysis of lateral brace tube. During the pre-forming stage, when the internal pressure was less than 65 MPa, the tube could not successfully expand due to insufficient internal pressure. When the internal pressure was more than 65 MPa, stress concentration existed in the middle bulging area of tube, which was not conducive to the subsequent bulging of tube. Therefore, the reasonable loading path in the pre-forming stage was normal pressure of 65 MPa. In the final bulging stage, the bulging results under the normal pressure loading path were not ideal, while the ideal bulging results could be obtained for both annealed and unannealed parts under multi-linear loading path 4. Therefore, the multi-linear loading path 4 was the reasonable loading path for final bulging. Compared with normal pressure loading, the forming effect of tube is better when multi-linear high pressure loading is used in the final bulging stage. Annealing treatment before final bulging reduces the residual stress of the bulging tube and makes the wall thickness distribution more uniform.