薄壁筒形件错距旋压有限元仿真模型构建方法研究（英文）

A study of 3D finite element modeling method for stagger spinning of thin-walled tube

目的:探究错距旋压仿真模型关键特性参数影响,改进建模方法,克服现有模型方案的缺陷,构建更准确、可靠和稳定的错距旋压有限元仿真模型。创新点:1.提供包括全模型、六面体离散、速度边界、全仿真、双精度和无干涉模型等在内的改进有限元模型构建方法;2.基于所构建的改进模型,完善错距值对成型过程影响的现有结论。方法:1.通过能量、网格独立性和过程参数分析,验证改进有限元模型的可行性和可靠性;2.通过对比仿真和数据分析,获得边界模式、精度模式、时间截断和错距干涉对仿真结果的影响;3.通过仿真模拟,完善现有受干涉、单精度、时间截断和位移边界影响的错距值研究成果。结论:1.速度边界模式较之位移边界模式具有更高的计算精度和效率;2.时间截断不能确保获取稳态结果,不利于计算的准确性和稳定性;3.截断误差对错距旋压成型结果影响显著,计算过程中应采用双精度模式;4.错距干涉严重干扰计算的正确性和可靠性,应在实验设计阶段予以排除;5.针对现有错距值研究受干涉、单精度、时间截断和位移边界影响的现状,基于改进模型,完善错距影响结论(表11)。

A modified 3D finite element （3D-FE） model is developed under the FE software environment of LS-DYNA based on characteristics of stagger spinning process and actual production conditions. Several important characteristics of the model are proposed, including full model, hexahedral element, speed boundary mode, full simulation, double-precision mode, and no-interference. Modeling procedures and key technologies are compared and summarized： speed mode is superior to displacement mode in simulation accuracy and stability; time truncation is an undesirable option for analysis of the distribution trend of time-history parameters to guarantee that the data has reached the stable state; double-precision mode is more suitable for stagger spinning simulation, as truncation error has obvious effects on the accuracy of results; interference phenomenon can lead to obvious oscillation and mutation simulation results and influence the reliability of simulation significantly. Then, based on the modified model, some improvements of current reported results of roller intervals have been made, which lead to higher accuracy and reliability in the simulation.