Roll forming is a sheet metal forming operation that incrementally forms flat sheets into a desired profile geometry. The process is characterized by a high material utilization and a high output quantity. Concomitant with these advantages, profile defects such as bow and twist of the profile can occur. In the literature, an inhomogeneous longitudinal strain distribution across the profile cross-section is considered to be the cause of these defects. However, a quantitative cause and effect analysis is missing up to now. This paper presents an analytical model that shows a quantitative relationship between profile defects and the underlying longitudinal strain distributions. The model can be used to calculate the longitudinal strain distribution of a roll-formed profile across its cross-section based on given values for bow and twist or vice versa. It is compared with results from simulations and experiments and clearly reveals the cause for twist and bow in roll forming.

Graphical abstract

中文翻译：

---

辊压成形纵向应变分布不均匀引起的型材缺陷

辊压成型是一种金属板材成型操作，可将平板逐渐成型为所需的轮廓几何形状。该工艺的特点是材料利用率高，产量高。伴随这些优点，可能会出现轮廓缺陷，例如轮廓的弯曲和扭曲。在文献中，型材横截面上的不均匀纵向应变分布被认为是造成这些缺陷的原因。然而，到目前为止，还缺少定量的因果分析。本文提出了一个分析模型，该模型显示了剖面缺陷与潜在纵向应变分布之间的定量关系。该模型可用于根据给定的弓形和扭曲值计算轧制型材横截面的纵向应变分布，反之亦然。

图形概要