The Materials panel allows you to specify the properties of the metal to be formed. For the stress strain curve, you can either supply a set of data points or the values for the parameters used in the Krupkowski-Swift hardening law. The altair_mat.db file, located in the bin directory, is a library of materials commonly used in stamping. All the relevant properties for each material are included in this file. You can also create new material libraries in your directory that can be accessed from any HyperForm model file.
Strain hardening is modeled using the Krupkowski-Swift law:
Planar anisotropy is modeled using directional Lankford coefficients, . An average r value is determined from these coefficients using the formula: r= [r0 + 2r45 + r90]/4. Normal anisotropy of the material is modeled using an average plastic strain ratio, r.
r0 = X axis
r90 = Y axis
It is suggested to rotate your part in order to make the rolling direction (r0) coincident with the X axis.
Some material properties can be calculated from other material property values. Those properties are indicated on the panel with an asterisk (*).
Data Type |
Input Parameters |
String |
Material Name |
Real |
Yield Stress, YS |
Real |
Tensile Stress, TS |
Real |
Poisson’s Ratio, nu |
Real |
Lankford coefficients, |
Real |
Plastic Strain Ratio, r |
Real |
Young’s Modulus, E |
Real |
Strength Coefficient, |
Real |
Strain-Hardening Exponent, n |
Real |
Pre-Strain Coefficient, |
Note: | The material characteristics are dependent on the unit of length and force chosen for the model. The material database given with HyperForm is consistent with models where length is expressed in millimeters (mm) and force is expressed in newtons (N). |