MATX27

Bulk Data Entry Defines additional material properties for elastic-plastic brittle material for geometric nonlinear analysis.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
MAT1	127	60.4		0.33	2.70E-06
MATX27	127	0.09026	0.22313	0.374618	100.0	0.175

Field	Contents	SI Unit Example
`MID`	Material ID of the associated MAT1. 1 No default (Integer > 0)
`A`	Plasticity yield stress. (Real > 0)
`B`	Plasticity hardening parameter. (Real ≥ 0)
`N`	Plasticity hardening exponent. Default = 1.0 (Real ≤ 1.0)
`EPSMAX`	Failure plastic strain $ε_{\max}$ . Default = 10³⁰ (Real > 0)
`SIGMAX`	Maximum plastic stress $σ_{\max 0}$ . Default = 10³⁰ (Real > 0)
`C`	Strain rate coefficient. Default = 0.0 (Real)
`DEPS0`	Reference strain rate ${\dot{ε}}_{0}$ . Default = 0.0 (Real) If `DESPS` ≤ `DESPS0`, no strain rate effect.
`ICC`	Strain rate dependency of $σ_{\max}$ flag. 4 OFF ON (Default)
`EPS1`	Tensile failure strain in principal strain direction 1. Default = 1.0*10³⁰ (Real > 0)
`EPS1MAX`	Maximum tensile failure strain in principal strain direction 1. Default = 1.1*10³⁰ (Real > 0)
`DMAX1`	Maximum tensile failure damage in principal strain direction 1. Default = 0.999 (Real > 0)
`EPSD1`	Tensile strain for element deletion in principal strain direction 2. Default = 1.2*10³⁰ (Real > 0)
`EPS2`	Tensile failure strain in principal strain direction 2. Default = 1.0*10³⁰ (Real > 0)
`EPS2MAX`	Maximum tensile failure strain in principal strain direction 2. Default = 1.1*10³⁰ (Real > 0)
`DMAX2`	Maximum tensile failure damage in principal strain direction 2. Default = 0.999 (Real > 0)
`EPSD2`	Tensile strain for element deletion in principal strain direction 2. Default = 1.2*10³⁰ (Real > 0)

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.
MATX27 is only applied in geometric nonlinear analysis subcases which are defined by ANALYSIS=EXPDYN. It is ignored for all other subcases.
This law is only applicable with shell elements. The isotropic elasto-plastic model is the same as with MATX02. However, MATX27 allows material damage and brittle failure to be modeled.

ICC controls the strain rate effect.

Figure 1.

$\begin{array}{l} σ = σ_{y} (1 + cIn (\frac{\dot{ε}}{{\dot{ε}}_{0}})) \\ σ_{\max} = σ_{\max 0} (1 + cIn \frac{\dot{ε}}{{\dot{ε}}_{0}}) \end{array}$	$\begin{array}{l} σ = σ_{y} (1 + cIn (\frac{\dot{ε}}{{\dot{ε}}_{0}})) \\ σ_{\max} = σ_{\max 0} \end{array}$

The failure plastic strain EPSMAX has no effect if the second continuation is defined.
An element is removed if one layer reaches the tensile failure strain EPS1.

Figure 2.
This card is represented as an extension to a MAT1 material in HyperMesh.