Incremental sheet forming (ISF), a promising and flexible forming method, is generally restricted by the unsatisfied geometric deviation for industrial applications; therefore, effective control and accurate prediction of geometric deviation in ISF are essential for quality improvement. However, the geometric deviation in ISF is extremely sensitive to the geometric shape, toolpath, and process parameters, which is challenging to predict and control. In this study, the comprehensive geometric-related mechanisms in ISF were analyzed, including springback after local bending of the bent and contact zones, and the elastic deflection of the inclined wall, particularly the associated deformation in the weak-stiffness region. Through a creative equivalent mapping method for calculating the elastic deflection of complex structures and modeling the bending moment distribution in different zones, an analytical model was developed to accurately and universally predict the geometric deviations of parts by ISF. Based on the results of the experiments and comparative studies using a response surface model, the proposed model provided superior capability for predicting the geometric accuracies of parts made using ISF with different sheet materials, process parameters, and geometric shapes, even for complex parts with non-axisymmetric structures and stepped features. The geometric-related mechanisms, forming characteristics, and influences of crucial parameters in ISF are discussed by adopting an analytical model combined with numerical simulations, demonstrating that the elastic deflection on the inclined wall, particularly the associated deformation in the weak-stiffness region, plays a primary role in the geometric deviation of complex parts compared with other geometric-related mechanisms.

中文翻译：

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增量板材成形过程中的几何偏差：分析建模和实验

增量板料成形（ISF）是一种很有前途且灵活的成形方法，但普遍受到几何偏差不满足工业应用的限制；因此，有效控制和准确预测ISF的几何偏差对于提高质量至关重要。然而，ISF中的几何偏差对几何形状、刀具路径和工艺参数极其敏感，预测和控制具有挑战性。在这项研究中，分析了ISF中与几何相关的综合机制，包括弯曲和接触区域局部弯曲后的回弹，以及倾斜壁的弹性挠度，特别是弱刚度区域的相关变形。通过创新的等效映射方法计算复杂结构的弹性挠度并对不同区域的弯矩分布进行建模，开发了一种分析模型，可以通过ISF准确、通用地预测零件的几何偏差。基于使用响应面模型的实验和比较研究的结果，所提出的模型提供了卓越的能力，可以预测使用不同板材、工艺参数和几何形状的 ISF 制造的零件的几何精度，甚至对于非金属材料的复杂零件也是如此。 -轴对称结构和阶梯特征。采用解析模型与数值模拟相结合的方法，讨论了ISF的几何相关机制、形成特征以及关键参数的影响，证明斜壁上的弹性挠度，特别是弱刚度区域的相关变形，在ISF中发挥着重要作用。与其他几何相关机构相比，在复杂零件的几何偏差中起着主要作用。