Elastoplastic Materials—Creo Ansys Simulation
Metals like steel exhibit elastic behavior for small loads. When the load is further increased the material can undergo plastic deformation. Such materials are called elastoplastic materials.
Isotropic hardening laws are used to define elastoplastic materials. Hardening laws are rules that describe the relationship between the flow stress and the effective strain for a material. For hardening materials, the yield surface evolves in space. The yield surface expands in all directions in proportion to the strain increment.
When defining elastoplastic materials for a study to be run in Creo Ansys Simulation you must be aware of the following:
• Creo Ansys Simulation only supports elastoplastic materials that use the Linear Hardening law in the material definition.
• Plastic strain result types are now available for a study that uses elastoplastic materials.
• Shell and shell pairs can be assigned elastoplastic materials but they must be planar parallel shells only and must be aligned to the axis of a coordinate system.
• Beams can be assigned elastoplastic materials. The beams must be straight beams only. Curved beams or beams that are not aligned with the axis of a coordinate system are not supported.
To define an elastoplastic material select Isotropic as the symmetry type and select Elastoplastic as the Stress-Strain Response on the Material Definition dialog box.
Use one of the following methods to define an elastoplastic material:
• Using Test Data—Select the Define By Tests check box and click Edit. The Plastic Hardening Law Definition dialog box opens. Select Linear Hardening as the hardening law to be used. Specify stress and strain values from test data to find the best-fit curve for a material model. You need to specify only the data at the yield point and for the plastic part of the stress-strain curve.
• Using Material Constants—Clear the Define By Tests check box, select Linear Hardening. and specify the value for Tangent Modulus. The tangent modulus has the same units as Young's modulus.
Fit the Tangent Modulus to the curve if you use test data to define the material. If you clear the Define By Tests check box, you must enter a constant value for Tangent Modulus.
The value of the tangent modulus is greater than 0 but less than Young’s modulus.
You must also specify the
Coefficient of Thermal Softening and the
Tensile Yield Stress for an elastoplastic material.