a comparative study on the formability prediction of two-layer metallic sheets

two-layer metallic sheets have wide applications in aerospace, marine, automotive and domestic industries due to their superlative characteristics. in this paper, the formability of two-layer sheet is investigated through analytical, experimental and numerical approaches. an analytical model is developed based on marciniak-kuczynski method associated hill’s non-quadratic yield criterion. forming limit diagrams are also obtained numerically based on finite element method using bifurcation theory and ductile fracture criteria. furthermore, experiments are carried out on al3105-st14 two-layer sheet. theoretical results from various methods are compared with results obtained from experiments to evaluate the competency of discussed analytical and numerical methods to predict the formability of two-layer sheets. the results show that analytical and numerical approaches discussed in this paper have good capabilities to predict the formability of two-layer sheets. however, the analytical method based on m-k model and numerical approach based on bifurcation theory are more suitable to determine the forming limit diagram of al3105-st14 two-layer sheets.