Numerical predictions and experimental validations of ductile damage evolution in sheet metal forming processes

Numerical Predictions of the Occurrence of Necking in Deep Drawing Processes

“…Note that the experimental results given by Aboutalebi et al [30] are obtained using the same Erichsen deep drawing test used in the simulations, which allows consistent comparison between the predicted FLDs and the experimental data. It can be noticed, in general, that the numerical predictions of the FLDs obtained by the Erichsen deep drawing tests are closer to the experimental results than those predicted by simple sheet stretching tests.…”

“…Numerical strain paths predicted by FE simulation of (a) the simple sheet stretching test and (b) the Erichsen deep drawing test with the various specimen widths. Figure 18 compares the predicted FLDs for the studied material, based on the simulations of both simple sheet stretching and Erichsen tests, along with the experimental results provided by Aboutalebi et al [30]. The FLDs based on the analyses of thickness strain, second time derivative of thickness strain, and critical damage threshold are presented in Figure 18a-c, respectively.…”

“…First, simple sheet stretching simulations, based on the different specimens, are performed. Then, the simulation of the deep drawing process, according to the Erichsen test (see, e.g., [29,30]), is conducted with the same specimens described above.…”

“…The friction coefficient between the tools and the specimen is taken to be equal to 0.15 [30]. Due to the symmetry of the problem, only one quarter of the geometry is discretized for each specimen.…”

“…As to the third numerical criterion, it relies on a critical damage threshold, at which is associated the occurrence of necking. All points of the predicted FLDs, which are obtained using the FE simulations combined with the numerical necking criteria, are compared with the experimental results taken from [30].…”