An analytical approach to predict web-warping and longitudinal strain in flexible roll formed sections of variable width
An analytical approach to predict web-warping and longitudinal strain in flexible roll formed sections of variable width
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DOI：
10.1016/j.ijmecsci.2014.11.010
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发表时间：
2015
影响因子：
7.3
通讯作者：
J. Jiao;B. Rolfe;J. Mendiguren;M. Weiss
中科院分区：
文献类型：
--
作者：
J. Jiao;B. Rolfe;J. Mendiguren;M. Weiss
为了减轻重量和提高乘客安全，汽车行业越来越需要使用超高强度钢(UHSS)来制造结构和碰撞部件。然而，超高速钢的成形能力有限，常规冲压成形难度大，限制了其应用。从UHSS制造结构汽车车身零件的另一种方法是柔性辊压成形工艺，该工艺允许将高强度和有限延展性的金属板材制造成复杂的重量优化的部件。UHSS柔性辊弯成形中的一个主要问题是腹板翘曲缺陷，即腹板区域高度在型材长度上的偏差。结果表明，腹板翘曲强烈依赖于凸缘上形成的永久纵向应变。柔性辊弯成形是一个具有多个辊架的连续过程，这使得数值分析非常耗时和计算量大。因此，在应用有限元分析之前的早期工艺设计阶段，建立腹板翘曲的分析模型对于提高设计效率至关重要。本文首次建立了变宽度型材柔性辊弯变形预测的解析模型。该模型是基于对零件法兰的纵向边缘应变进行评估的。然后将这些信息与一个简单的几何模型结合使用，以研究腹板翘曲和纵向应变与工艺参数之间的关系。
To reduce weight and improve passenger safety there is an increased need in the automotive industry to use Ultra High Strength Steel (UHSS) for structural and crash components. However, the application of UHSS is restricted by their limited formability and the difficulty of forming them in conventional stamping. An alternative method of manufacturing structural auto body parts from UHSS is the flexible roll forming process, which allows the manufacture of metal sheet with high strength and limited ductility into complex and weight-optimized components. One major problem in the flexible roll forming of UHSS is the web-warping defect, which is the deviation in height of the web area over the length of the profile. It has been shown that web-warping is strongly dependant to the permanent longitudinal strain formed in the flange of the part. Flexible roll forming is a continuous process with many roll stands, which makes numerical analysis extremely time intensive and computationally expensive. An analytical model of web-warping is therefore critical to improve design efficiency during the early process design stage before FEA is applied. This paper establishes for the first time an analytical model for the prediction of web-warping for the flexible roll forming of a section with variable width. The model is based on evaluating longitudinal edge strain in the flange of the part. This information is then used in combination with a simple geometrical model to investigate the relationship between web-warping and longitudinal strain with respect to process parameters.