ABSTRACT Despite good creep and fatigue durability, high resistance against chemicals and good surface finish, Polyoxymethylene (POM) has been sidelined in incremental sheet forming (ISF) literature due to its low formability at room temperature. This paper addresses the issue by deploying a cost-effective friction-induced heat at the tool-sheet interface. This work demonstrates a combined experimental, analytical, and numerical approach to investigate the effects of elevated temperature in ISF of POM. For this purpose, the formability of POM was first experimentally investigated under the interactive effects of the process parameters. Employing the membrane analysis approach, the stress state in the FSISF process was defined. The tool-sheet contact area was calculated as a function of toolpath and the relevant process parameters. The Johnson-Cook plasticity model was calibrated based on several universal mechanical tests at various temperatures and rates. Embedding the stress state, contact area, and the material model inside an algorithm developed by adopting the Finite Difference Method, force, friction-induced heat, and temperature at the tool-sheet interface were evaluated. Simulation results were validated by experimental outcomes. A threshold boundary for the maximum allowable tooltip temperature was established to avoid heat-induced defects while ensuring the sheet formability.

中文翻译：

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聚甲醛的摩擦搅拌渐进成型：工艺输出、力和温度

摘要 尽管聚甲醛 (POM) 具有良好的蠕变和疲劳耐久性、对化学品的高耐受性和良好的表面光洁度，但由于其室温下的低成型性，在渐进式板材成型 (ISF) 文献中已被排除在外。本文通过在工具表界面部署具有成本效益的摩擦引起的热量来解决这个问题。这项工作展示了一种结合实验、分析和数值方法来研究高温对 POM 的 ISF 的影响。为此，首先在工艺参数的交互作用下对 POM 的可成形性进行了实验研究。采用膜分析方法，定义了 FSISF 过程中的应力状态。刀具板接触面积计算为刀具路径和相关工艺参数的函数。Johnson-Cook 塑性模型基于不同温度和速率下的几种通用机械测试进行校准。将应力状态、接触面积和材料模型嵌入到采用有限差分法开发的算法中，对工具-板界面处的力、摩擦热和温度进行了评估。仿真结果得到了实验结果的验证。建立了最大允许工具提示温度的阈值边界，以避免热引起的缺陷，同时确保板材的可成形性。和工具表界面的温度进行了评估。仿真结果得到了实验结果的验证。建立了最大允许工具提示温度的阈值边界，以避免热引起的缺陷，同时确保板材的可成形性。和工具板界面处的温度进行了评估。仿真结果得到了实验结果的验证。建立了最大允许工具提示温度的阈值边界，以避免热引起的缺陷，同时确保板材的可成形性。