Mechanisms and forming rules of large thin-walled aluminum alloy components in electromagnetic incremental forming

摘要

Electromagnetic incremental forming is provided with the superiorities of improving the forming limit of materials and extending the scope of component dimension, and thus is a promising technique to realize high quality precision forming of large thin-walled aluminum components used in aviation and aerospace fields. However, electromagnetic incremental forming is a multi-parameter affected and multi-step complex dynamic forming process in which sheet metal undergoes repeated high velocity current-carrying local deformation, unloading and springback. With the change of multi-step processing parameters, the macro-plastic flow and micro-defects evolution behaviors change significantly, which brings about severe challenge to forming quality control. To this end, a macro-micro numerical model of the electromagnetic incremental forming process of large thin-walled aluminum components is established by introducing a micro-defects evolution coupled constitutive model for current-carrying dynamic deformation of aluminum alloy. By finite element simulation, the effect rules of multi-step discharging parameters, geometric parameters and discharging path on the forming profile and forming uniformity of the component are studied. Moreover, the correlation between the complex time-space distribution of electromagnetic field and forming quality indices are determined. Ultimately, an optimized electromagnetic incremental forming scheme is proposed and experimentally validated considering the comprehensive forming quality of large thin-walled aluminum components.