To lighten and stiffen the structural components used in automobile bodies, the variable curvature local-induction-heating bending forming (VC-LIHBF) technology was developed. However, few studies have been conducted on the optimization of the structural and geometric parameters of the inductor and the parameters of the LIHBF process. This paper focuses on the improvement of the cross-sectional distortion and the forming limit of the thin-walled rectangular steel tubes (TWRSTs) without the mandrel support. In this work, a coupled thermo-mechanical finite element analysis (FEA) method is developed to investigate the structural and geometric parameters of the inductor and the deformation behavior during VC-LIHBF. The temperature distribution is calculated by the electromagnetic and heat transfer analysis, and the stress distribution is obtained by the deformation analysis. Experiments were carried out to validate the reliability of the proposed finite element model (FEM). The results indicate that the forming quality of the TWRST is significantly affected by the structural and geometric parameters of the inductor, the feed rate of the tube, the push speed of the bending roller and the distance between the inductor and the bending roller. The appropriate inductor and process parameters for a B1500HS TWRST were determined. The findings of this study may provide important guidance for practical manufacturing via the LIHBF process.

中文翻译：

---

B1500HS薄壁矩形钢管的局部感应加热弯曲过程：模拟和实验研究

为了减轻和加固汽车车身中使用的结构部件，开发了可变曲率局部感应加热弯曲成型（VC-LIHBF）技术。但是，很少有关于电感器的结构和几何参数以及LIHBF工艺参数的优化研究。本文致力于改善无心轴支撑的薄壁矩形钢管（TWRSTs）的截面变形和成形极限。在这项工作中，开发了一种热机械耦合有限元分析（FEA）方法，以研究感应器的结构和几何参数以及VC-LIHBF期间的变形行为。通过电磁和热传递分析计算温度分布，通过变形分析得到应力分布。进行实验以验证所提出的有限元模型（FEM）的可靠性。结果表明，TWRST的成形质量受感应器的结构和几何参数，管的进给速度，弯曲辊的推动速度以及感应器与弯曲辊之间的距离的影响很大。确定了B1500HS TWRST的合适电感和工艺参数。这项研究的结果可能为通过LIHBF工艺进行实际制造提供重要的指导。结果表明，TWRST的成形质量受感应器的结构和几何参数，管的进给速度，弯曲辊的推动速度以及感应器与弯曲辊之间的距离的影响很大。确定了B1500HS TWRST的合适电感和工艺参数。这项研究的结果可能为通过LIHBF工艺进行实际制造提供重要的指导。结果表明，TWRST的成形质量受感应器的结构和几何参数，管的进给速度，弯曲辊的推动速度以及感应器与弯曲辊之间的距离的影响很大。确定了B1500HS TWRST的合适电感和工艺参数。这项研究的结果可能为通过LIHBF工艺进行实际制造提供重要的指导。