# MATX36

Bulk Data Entry Defines additional material properties for piece-wise linear elastic-plastic material for geometric nonlinear analysis.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
MATX36 MID EPSMAX EPST1 EPST2 EPSF FSMOOTH FCUT ICH
TPID PSCA
TID1 FSCA1 EPSR1
etc etc etc
TIDi FSCAi EPSRi

## Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
MAT1 102 60.4   0.33 2.70E-06
MATX36 102
10 1.0
7 1.0 0.0

## Definitions

Field Contents SI Unit Example
MID Material identifier of the associated MAT1. 1

No default (Integer > 0)

EPSMAX Failure plastic strain ${\epsilon }_{\mathrm{max}}$ .

Default = 1030 (Real > 0)

EPST1 Maximum tensile failure strain. 5

Default = 1030 (Real > 0)

EPST2 Maximum tensile failure damage. 6

Default = 2.0*1030 (Real > 0)

EPSF Tensile strain for element deletion.

Default = 3.0*1030 (Real > 0)

FSMOOTH Strain rate smoothing flag.
OFF (Default)
ON

FCUT Cutoff frequency for strain rate filtering. Only for shell and solid elements.

Default = 1030 (Real ≥ 0)

ICH Hardening coefficient.
0.0 (Default)
The hardening is a full isotropic model.
1.0
Hardening uses the kinematic Prager-Ziegler model.
Between 0.0 and 1.0
Hardening is interpolated between the two models.

(Real > 0)

TPID Identification number of a TABLES1 that defines pressure dependent yield stress function.

No default (Integer > 0)

PSCA Scale factor for stress in pressure dependent function.

Default = 1.0 (Real)

TIDi Identification number of a TABLES1 that defines the yield stress versus plastic strain function corresponding to EPSRi. Separate functions must be defined for different strain rates.

No default (Integer > 0)

FSCAi Scale factor for TIDi.

Default = 1.0 (Real)

EPSRi Strain rate. Strain rate values must be given strictly in ascending order.

(Real)

1. The material identification number must be that of an existing MAT1 Bulk Data Entry. Only one MATXi material extension can be associated with a particular MAT1.
2. MATX36 is only applied in geometric nonlinear analysis subcases which are defined by ANALYSIS=EXPDYN. It is ignored for all other subcases.
3. The first point of yield stress functions (plastic strain versus stress) should have a plastic strain value of zero. If the last point of the first (static) function equals 0 in stress, the default value of EPSMAX is set to the value of the corresponding plastic strain.
4. When the plastic strain reaches EPSMAX, the element is deleted.
5. If the first principal strain ${\epsilon }_{1}$ reaches $\text{ε}$ t1 = EPST1, the stress $\sigma$ is reduced by:(1)
$\sigma =\sigma \left(\frac{{\epsilon }_{\text{t}2}-{\epsilon }_{1}}{{\epsilon }_{\text{t}2}-{\epsilon }_{\text{t}1}}\right)$
with $\text{ε}$ t2 = EPST2.
6. If the first principal strain ${\epsilon }_{1}$ reaches $\text{ε}$ t2 = EPST2, the stress is reduced to 0 (but the element is not deleted).
7. If the first principal strain ${\epsilon }_{1}$ reaches $\text{ε}$ f = EPSF, the element is deleted.
8. Strain rate filtering is used to smooth strain rates. The input FCUT is available only for shell and solid elements.
9. Hardening is defined by ICH.
10. The kinematic hardening model is not available with global formulation (NIP=0 on PSHELX), that is hardening is fully isotropic.
11. In case of kinematic hardening and strain rate dependency, the yield stress depends on the strain rate.
12. TPID is used to distinguish the behavior in tension and compression for certain materials (that is pressure dependent yield). This is available for both shell and solid elements. The effective yield stress is then obtained by multiplying the nominal yield stress by the yield factor PSCA corresponding to the actual pressure.
13. The first function TID1 is used for strain rate values from 0 to the corresponding strain rate EPSR1. However, the last function used in the model does not extend to the maximum strain rate; for higher strain rates, a linear extrapolation will be applied. Hence, if ${\stackrel{˙}{\epsilon }}_{0}$EPSRi, the yield stress is interpolated between TIDi and TIDi-1. If ${\stackrel{˙}{\epsilon }}_{0}$EPSR1, TID1 is used. Above EPSRAX the yield stress is extrapolated.
14. Strain rate values must be given strictly in ascending order. Separate functions must be defined for different strain rates.
15. At least one strain rate is needed under which the yield stress versus plastic strain function is defined.
16. This card is represented as a material in HyperMesh.