This plasticity material model is often used in large strain analyses. A bilinear stress-strain curve requires that you input the Yield Strength and Tangent Modulus . The slope of the first segment in the curve is equivalent to the Young's modulus of the material while the slope of the second segment is the tangent modulus.

This material behavior is written as *MAT_PLASTIC_KINEMATIC . The parameter beta of this keyword is set to 1.

Custom results variables available for this model:

*Resultant value over shell/beam section.

This plasticity material model is often used in large strain analyses. Do not use this model for cyclic or highly nonproportional load histories in small-strain analyses.

You must supply the data in the form of plastic strain vs. stress. The first point of the curve must be the yield point, that is, zero plastic strain and yield stress. The slope of the stress-strain curve is assumed to be zero beyond the last user-defined stress-strain data point. No segment of the curve can have a slope of less than zero.

Custom results variables available for this model:

*Resultant value over shell/beam section.

This plasticity material model assumes that the total stress range is equal to twice the yield stress, to include the Bauschinger effect. This model may be used for materials that obey Von Mises yield criteria (includes most metals). The tangent modulus cannot be less than zero or greater than the elastic modulus.

This material behavior is written as *MAT_PLASTIC_KINEMATIC . The parameter beta of this keyword is set to 0.

Custom results variables available for this model:

*Resultant value over shell/beam section.

See Johnson-Cook Strength for information about this model. However, the strain rate correction parameter described in this material model is not used by LS-DYNA.

This material behavior is written as *MAT_JOHNSON_COOK or *MAT_SIMPLIFIED_JOHNSON_COOK depending on whether it is used in combination with an equation of state or not. The simplified form is used when no equation of state is defined. The thermal terms are discarded in that scenario.

Custom results variables available for this model:

*Resultant value over shell/beam section.

**Temperature will be non-zero only if a specific heat capacity is defined.

The Cowper-Symonds power law hardening lets you define plastic behavior with bilinear isotropic hardening and power law hardening defined with strength coefficient K and hardening coefficient n. Strain rate effects are accounted for by the Cowper-Symonds strain rate parameters, C and P.

Yield surface can be scaled for strain rate dependence or the latter can be defined using a fully visco-plastic formation.

This material behavior is written as *MAT_POWER_LAW_PLASTICITY .

Custom results variables available for this model:

*Resultant value over shell/beam section.

Strain rate dependent plasticity model typically used for superplastic forming analyses. The material model follows a Ramburgh-Osgood constitutive relationship of the form:

where:

k is the material coefficient,

m is the hardening coefficient,

n is the strain rate parameter.

This material behavior is written as *MAT_RATE_SENSITIVE_POWERLAW_PLASTICITY .

This model is very efficient in solution and is most commonly used in crash simulations. It is similar to the multilinear isotropic hardening behavior. Stress-strain behavior is defined with a load curve of effective true stress versus effective plastic true strain. Failure strain can be input for which elements will be eliminated. Yield surface can be scaled for strain rate dependence by the Cowper-Symonds model.

This material behavior is written as *MAT_ PIECEWISE_LINEAR_PLASTICITY , where the parameter lcss is the curve id of the effective stress versus plastic strain.

This model is an enhanced version of the Cowper Symonds Piecewise Linear model that accounts for multiple failure methods:

The plastic strain failure parameter of this material model is defined by adding a plastic strain failure behavior to it.

This material behavior is written as *MAT_ MODIFIED_PIECEWISE_LINEAR_PLASTICITY , where the parameter lcss is the curve id of the effective stress versus plastic strain.