A study on localized expansion defects in tube hydroforming

作者：Lin Sin Liang; Chen Zih Wei; Chen Fuh Kuo^*

来源：Journal of the Chinese Institute of Engineers, 2018, 41(2): 149-159.

DOI：10.1080/02533839.2018.1437367

• Tube hydroforming
• localized expansion
• preforming
• finite-element method (FEM)

This study investigated localized expansion in the tube hydroforming process, which may induce cracks in the tube material. First, a model of a trailing arm in the front subframe was built using the finite-element method; it was compared with the actual component to verify the accuracy of the model. Subsequently, a localized expansion model was constructed to analyze the effects of the tube geometry parameters and material-hardening parameters on localized expansion and the fracture location. The simulation results indicated that localized expansion can be ameliorated by changing the material distribution of the tube using a preform or an inner die; these methods substantially reduced the maximum material thinning. However, these methods can only be applied to the local bulging area that occurs when both sides of the tube are constrained. When both sides are not constrained, the material bulges back to the original state, and localized expansion occurs. In this study, both sides of the localized expansion area of the trailing arm in the front subframe were constrained, and the material distribution of the fracture zone could be changed by moving the mandrel to improve the localized expansion-induced fracture characteristics. Experimental results successfully validated the proposed method and analysis.

• 出版日期2018