Blank shape determining method, blank, press formed product, press forming method, computer program, and recording medium

A computer program performing:

• using a calculation device,
• a first calculating process of making a forming analysis of forming a reference blank (B0) into a reference formed product (P0) on the basis of material parameters, forming conditions, and analytical models, and acquiring a sheet thickness distribution (DT) and a plastic strain distribution (DS);
• a first forming failure evaluation index acquiring process of acquiring a forming failure evaluation index (I) for the reference blank (B0) on the basis of the sheet thickness distribution (DT) and the plastic strain distribution (DS) that are acquired in the first calculating process;
• a forming failure region estimating process of estimating a region, which includes an end edge portion (αE) at which the forming failure evaluation index (I) exceeds a predetermined threshold within the reference blank (B0), as a forming failure region (α);
• a corrected blank generating process of generating a plurality of corrected blanks (Bi) (where i=1, 2, 3 . . . n), in each of which a shape of the end edge portion (αE) is corrected;
• a second calculating process of making a forming analysis of forming the plurality of corrected blanks (Bi) into corrected formed products (Pi) on the basis of the material parameters, the forming conditions, and the analytical models, and acquiring the sheet thickness distribution (DT) and the plastic strain distribution (DS);
• a second forming failure evaluation index acquiring process of acquiring the forming failure evaluation index (I) for the corrected formed products (Pi) on the basis of the sheet thickness distribution (DT) and the plastic strain distribution (DS) that are acquired in the second calculating process;
• and
• a blank shape determining process of determining a shape of the corrected blank (Bi) having a smallest maximum value of the forming failure evaluation index (I) as a shape of a blank (B) provided for press forming.