Investigating spring back phenomena in double curved sheet metals forming

Characterization of electrolytic tinplate materials via combined finite element and regression models

“…Tables 5 and 6 also show the errors in the estimation of R m (MAPE of 7.77% and 3.03% for single and double reduced tinplates, respectively) and E Rm (MAPE of 9.36% and 7.88% for single and double reduced tinplates, respectively) obtained from the prediction of R p0:2 and equations (7) and (8). Figure 7 shows, for some of the tinplate samples used in Table 5 Figure 7 clearly shows that the errors in the prediction of R p0:2 obtained from equation (2) with respect to the values obtained in the tensile test are much larger (30.88% and 12.83% of MAPE for single and double reduced tinplates, respectively) than those from the proposed method (MLP).…”

“…1,2 This quasi-static assumption is commonly used by many researchers to simulate the spring-back test and has been proven to be valid. [6][7][8][9][10] The search for a convergent solution in the FE simulations requires the progressive application of the boundary conditions over two time steps. Figure 2(a) shows the bending sequence used in the FE simulation and is described in the following.…”

“…Figure 4 shows a pair of samples of true-stress versus true-strain curves for single ( Figure 4(a)) and double reduced tinplates (Figure 4(b)), which illustrate the parameters used for defining the behaviour of the tinplate material according to equations (7) and (8). In this figure, the tinplate materials shown are TS260 (single reduced) and TH430 (double reduced).…”

“…Once the best proposed model was selected, the values of R p0:2 were obtained and used to calculate the values of R m , and E Rm based on equations (7) and (8). Finally, the selected predictive model was tested with new data not belonging to the FE simulations, in order to obtain the actual prediction errors.…”

Large deformation analysis of functionally graded elastoplastic materials via solid tetrahedral finite elements

“…These materials have many engineering applications. At the automotive industry level, one can cite the sheet-metal forming processes, in which some automobile components acquire the desired shape via plastic deformation ( [1][2][3]). Functionally graded materials (FGMs) are special composites in which the composition and, thus, the mechanical properties vary gradually (smooth and continuously) over the volume.…”