Research on magnetorheological elastomer assisted flexible multi-point stretch-bending technology

Creasing defects in aluminum profiles post-forming significantly hinder their utilization. This study aimed to mitigate these defects by investigating the causes and mitigating strategies for two types of creases in aluminum profiles formed via flexible stretch bending with roller-type multi-point dies (FSBRD). To achieve dynamic control over the mold surface, magnetorheological elastomers (MREs) were employed to harness their magnetorheological effect, enabling adjustable mold hardness. The adjustable hardness of the mold, enabled by MREs, was investigated under varying magnetic inductions to form T-shaped profiles. The results quantitatively demonstrate that the addition of MREs significantly reduces crease defects, with a minimum value of thick direction strain not exceeding -0.1, and improves moulding quality. Specifically, at a profile thickness of 10mm, an optimal magnetic induction of 200mT minimized crease depth, while for a 66mm thickness, 400mT was most effective. It was also found that increasing the coefficient of friction between the MRE and the contour resulted in a decrease in crease depth and a decrease followed by an increase in crease height. Experimental validation confirmed the simulation accuracy, with thickness trends of the experimentally formed profiles closely matching the simulated ones. The study concludes that the FSBRD-M process is effective in controlling creases and expands the application of MREs in forming technology.