MAT1

Bulk Data Entry Defines the material properties for linear, temperature-independent, and isotropic materials.

Attention: Valid for Implicit and Explicit Analysis

Format


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
MAT1	`MID`	`E`	`G`	`NU`	`RHO`	`A`	`TREF`	`GE`
	`ST`	`SC`	`SS`
	`MODULI`	`MTIME`
	`RAYL`	`ALPHA`	`BETA`
	`UDATA`	`PARAM1`	`VALUE1`	`PARAM2`	`VALUE2`	etc.

Example


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
MAT1	17	3.+7		0.33	4.28

Definitions


Field	Contents	SI Unit Example
`MID`	Unique material identification. Integer Specifies an identification number for this material. <String> Specifies a user-defined string label for this material entry. 2 No default (Integer > 0 or <String>)
`E`	Young's modulus. Default = blank (Real or blank)
`G`	Shear modulus. Default = blank (Real or blank)
`NU`	Poisson's ratio. If < 0.0, a warning is issued. Default = blank (-1.0 < Real < 0.5 or blank)
`RHO`	Mass density. Used to automatically compute mass for all structural elements. No default (Real)
`A`	Thermal expansion coefficient. No default (Real)
`TREF`	Reference temperature for thermal loading. Default = 0.0 (Real)
`GE`	Structural element damping coefficient. 10 11 No default (Real)
`ST`, `SC`, `SS`	Stress limits in tension, compression and shear. Used for composite ply failure calculations. No default (Real)
`MODULI`	Continuation line flag for moduli temporal property. 12
`MTIME`	Material temporal property. This field controls the interpretation of the input material property for viscoelasticity. INSTANT This material property is considered as the Instantaneous material input for viscoelasticity on the MATVE entry. LONG (Default) This material property is considered as the Long-term relaxed material input for viscoelasticity on the MATVE entry.
`RAYL`	Continuation line flag for material-dependent Rayleigh damping.
`ALPHA`	Material-dependent Rayleigh Damping coefficient for the mass matrix. Default = blank (Real ≥ 0.0)
`BETA`	Material-dependent Rayleigh Damping coefficient for the stiffness matrix. Default = blank (Real ≥ 0.0)
`UDATA`	Flag indicating that user-defined material parameters for storage through the workflow are to follow. 15
`PARAMi`	Name of the user-defined material parameters for storage. Default = Blank (Alphanumeric string)
`VALUEi`	Value of the corresponding user-defined material parameters. Default = Blank (Real)

Comments

The material identification number/string must be unique for all MAT1, MAT2, MAT8 and MAT9 entries.
String based labels allow for easier visual identification of materials, including when being referenced by other cards. (example, the MID field of properties). For more details, refer to String Label Based Input File in the Bulk Data Input File.
Either E or G must be specified (that is, non-blank).
If any one of E, G, or NU is blank, it is computed to satisfy the identity,
E = 2(1+NU)G; otherwise, values supplied by you are used.
If E and NU are both blank, they are both given the value 0.0.
If G and NU are both blank, they are both given the value 0.0.
Unlikely data on one or more MAT1 entries result in a warning message. Unlikely data is defined as:
- E < 0.0 or
- G < 0.0 or
- NU > 0.5 or
- NU < -1.0 or
- $| 1 - \frac{E}{2 (1 + NU) G} | > 0.01$
- except for cases covered by comments 5 and 6.
It is strongly recommended that only two of the three values E, G, and NU be input.
The large field format may also be used.
To obtain the damping coefficient GE, multiply the critical damping ratio, $C / C_{0}$ by 2.0.
TREF and GE are ignored, if a MAT1 entry is referenced by a PCOMP, PCOMPP, or PCOMPG Bulk Data Entries.
MODULI continuation line is only applicable when used together with the MATVE entry. Refer to MATVE which provides additional information on how this material input is interpreted.
For material-dependent Rayleigh damping, the equivalent viscous damping, $C$ , is defined as:
$C = ALPHA * M + BETA * K$
Where,

$ALPHA$ and $BETA$

Defined on the RAYL continuation line on the material entry

$M$

Mass matrix

$K$

Stiffness matrix

Supported solutions for material-dependent Rayleigh damping on MAT1:
- Direct Frequency Response
- Modal Frequency Response
- Direct Transient Response
- Modal Transient Response
- Nonlinear Transient Analysis
- Explicit Dynamic Analysis
Note: For cohesive elements that reference MAT1, material-based Rayleigh damping is only supported for Nonlinear Transient Analysis.

This card is represented as a material in HyperMesh.


Element Type	E	NU	G
CROD, CBAR, CBEAM, and CWELD	Axial and Bending	N/A	Transverse Shear and Torsion
CSHEAR	N/A	N/A	Shear
CQUAD and CTRIA	Membrane and Bending	Membrane and Bending	Transverse Shear
CHEX, CTETRA, CPENTA, CPRYRA and CSEAM	Deformation		N/A

User-defined parameters and their corresponding values can be stored on the UDATA continuation line. They are visible if the input file is echoed out (via the ECHO command). They are not used in the analysis.