Effect of different yield criteria on prediction of wrinkling initiation of interstitial-free galvanized steel sheet

Thin interstitial-free (IF) galvanized steel sheets have great usage in auto industry due to their high formability and corrosion resistance. However presence of wrinkle waves in deep drawn parts of thin IF steel sheets is a common challenging issue. Achieving a reliable method to predict the wrinkling onset enables the manufacturers to avoid wrinkling by modification of forming parameters. In the present study, sidewall wrinkling of an IF-galvanized steel sheet was both analytically and experimentally examined during a conical cup wrinkling test. Using an energy method approach together with a newly developed deflection function, Hosford and Hill-1948 yield criteria were employed to predict the critical values of stress and cup height at the onset of wrinkling. According to the obtained results, applying Hill-1948 yield criterion resulted in prediction of wrinkling onset closer to the experimental value than Hosford yield criterion. It was also found that the newly presented deflection function has a great suitability for prediction of the real status of wrinkling phenomenon.