FEM Investigation of Ductile Fracture Prediction in Two-Point Incremental Sheet Metal Forming process

Abstract Two-point incremental sheet forming (TPIF) is an advanced forming technology for production of complex customized functional components in small batches for aircraft, biomedical and automobile applications. This paper is concerned with FEM damage modelling using VUMAT in Abaqus/Explicit for fracture prediction in TPIF. The enhanced Lemaitre damage model accounting for the effect of micro-crack closure is adopted to predict ductile fracture in TPIF with a varying wall angle hemispherical shape. The material constants in the damage model are calibrated by minimizing force error using a Newton approach in a tensile test. The TPIF simulation results with the enhanced Lemaitre damage model are validated by the thickness distribution, fracture location and forming force evolution trends. It is concluded that the enhanced CDM-based Lemaitre model can be used for ductile fracture of AA 7075 aluminium alloy in TPIF with a hemispherical shape.