Influence of superimposed hydrostatic tension on void growth in the neck of a metal sheet in biaxial stress fields. Part - I - Modelling

Forming Limit Differences in Hemispherical Dome and Biaxial Test During Equibiaxial Tension on Cruciform

“…From these literatures [12][13][14][15][16][17][18][19][20], it is concluded that the observed difference in biaxial and hemispherical dome test failure points in the present research can be explained by the pressurization effect that the punch has on the specimen during hemispherical dome forming. This effect is not present in specimens pulled on the biaxial machine, and, therefore, the ductility is not affected, and a lower formability and failure is seen.…”

“…The main difference in the hemispherical dome test as compared to the biaxial test is that the punch is in contact with the sheet metal, and it forces downward in order to deform the material by pressurizing the sheet surface. It is assumed that this difference is making the material deform more during the hemispherical dome tests than was found with the Some previous research [12][13][14][15][16][17][18][19][20] has observed that the application of pressure through the thickness direction can soften the material and increase its forming. As investigated in these literatures, the effect of pressurization on formability in sheet metals is a case that an effective softening of the material occurs to varying degrees, depending upon the amount of pressure that is applied to a given material through thickness direction.…”

“…This is an unwanted variable that can cause variations during testing and data collection [9][10][11]. Pressure is the other contact condition that can cause the sample to fail at higher forces or time because of how the pressure makes the material behave while under stress [12][13][14][15][16][17][18][19][20]. All referenced studies show that the through thickness normal stress influences the forming limit curve (FLC).…”