MATL8 (MCT Definition for Membrane and Shell Elements)

Description

The MATL8 entry defines the material properties for composite membrane and shell elements using the Multi-Continuum Theory (MCT)method. The MCT method is a multiscale approach to analysis of composites. Failure of the composite lamina is calculated by evaluating the stress state in either the fiber or in the matrix rather than the homogenized composite lamina. The MCT method does allow for the interaction of failure in the fiber and matrix. The MCT method is applicable to uni-directional and woven composites. High fidelity micromechanics models enable the generation and optimization of composite properties. The MCT ply failure analysis is enabled by specifying MCT in the FT field of the PCOMP entry.

Format

1	2	3	4	5	6	7	8	9	10
MATL8	MID	MIDM	MIDF	MIDC	FVF	TYPE		MCTMAT
	LC	L	D	T	W		FBVF	WBVF
	MIDX	MIDL	MIDW	MIDP

Example

MATL8	101	200	300	400	0.7	1		0.066
	1.E-2	1.E-2	1.E-3

Field	Definition	Type	Default
MID	Material identification number. Referenced on a PSHELL or PCOMP entry only.	Integer > 0	Required
MIDM	Material identification number for the matrix material. See Remark 4.	Integer	Required
MIDF	Material identification number for the reinforcement (fiber) material. See Remark 4.	Integer	Required
MIDC	Material identification number for the composite material. See Remark 4.	Integer	Required
FVF	Volume fraction of fiber.	0.3 ≤ Real ≤ 0.9	Required
TYPE	Reinforcement type, selected by one of the following values: 1 = Aligned continuous fibers 6 = Plain weave fabrics (MCT only) See Remarks 4 and 5.	Integer	1
MCTMAT	MCT material input, selected by one of the following values: 1 = Perform MCT optimization of input materials 2 = Use input materials without modification 3 = Use default Carbon/Epoxy fiber matrix 4 = Use default Glass/Epoxy fiber matrix 5 = use default Kevlar/Epoxy fiber matrix See Remarks 6, 7, and 9.	Integer	1
LC	Short fiber critical length.	Real ≥ 0.0	Required if TYPE = 3
L	Fiber length (not used).	Real ≥ 0.0	Required if TYPE = 3, 4, or 5
D	Fiber diameter (not used)	Real ≥ 0.0	Required if TYPE = 3 or 5
T	Fiber plate thickness (not used).	Real ≥ 0.0
W	Fiber plate width.	Real ≥ 0.0	Required if TYPE = 4
FBVF	Fill bundle volume fraction. See Remark 8.	0.2 ≤ Real ≤ 0.37	Required if TYPE = 6
WBVF	Warp bundle volume fraction. See Remark 8.	0.2 ≤ Real ≤ 0.37	FBVF
MIDX	(not used)	Integer > 0
MIDL	(not used)	Integer > 0
MIDW	(not used)	Integer > 0
MIDP	(not used)	Integer > 0

Remarks

1. The material identification number must be unique for all MATi entries.
2. The transverse shear moduli G1Z and G2Z are computed automatically from the in-plane shear modulus G12.
3. The MCT method is a multiscale approach to composites analysis. Failure in the composite lamina is calculated by evaluating the stress state in either the fiber or matrix, rather than the homogenized composite lamina, allowing one to capture interactions between the two. The method is applicable to unidirectional and woven composites. High fidelity micromechanics models enable the generation/optimization of composite properties from properties of the matrix and fiber. MCT ply failure analysis is enabled by specifying MCT in the FT field of the PCOMP entry.
4. MIDM and MIDF may reference either a MAT1 or MAT8 entry. For MAT1 entries the E, G, NU, and RHO fields must be non-zero. The A, ST, SC, and SS fields are optional. For MAT8 entries the E1, E2, NU12, GI12, and RHO fields must be non-zero. The A1, Xt, Xc, Yt, Tc, and S fields are optional. MIDC is required for the MCT method. MIDC must reference a MAT8 entry only. MIDC specifies properties for the generated MAT8 material that are not calculated. The material allowables (Xt, Xc, Yt, etc.) must be specified on the MAT8 referenced by MIDC if failure index/strength are desired.
5. The Type field defines the fiber type. Fiber types are detailed in the following table:

   TYPE	Description	Example
   1	Aligned continuous fiber composite lamina. Individual continuous fibers oriented in a defined direction.	Unidirectional graphite fibers in an epoxy resin.
   6	Plain weave composite lamina. Woven fabric, where fill and warp threads interlace alternately resulting in equal properties in each direction.	Graphite cloth in an epoxy resin.

6. The MCTMAT field affects how material properties specified on MIDM, MIDF, and MIDC are processed. When MCTMAT is set to 1 (default) MIDM and MIDF properties are optimized using a very high fidelity micromechanics model resulting in generated MIDC values. When MCTMAT is set to 2, the MIDM, MIDF, and MIDC values are assumed already optimized and no adjustment in values is made. MCTMAT set to 3, 4, or 5 provide optimized default values for common materials.
7. MCT default material properties (MCTMAT = 3, 4, or 5) require that PARAM, UNITS be specified for the correct selection of default material units corresponding to the model input material property units (see the Parameters section for more information on UNITS).
8. Material stability requires that if FBVF ≠ WBVF, then FBVF + WBVF ≤ .68. If this condition is not met a fatal error will be issued.
9. MCT default fiber and matrix material properties (MCTMAT = 3, 4, or 5) are listed in the following table in metric units:

   Variables	Carbon Fiber	Glass Fiber	Kevlar Fiber	Epoxy (Carbon)	Epoxy (Glass)	Epoxy (Kevlar)
   E1	2.3E+11 Pa	8.0E+10 Pa	8.0E+10 Pa	3.5E+9 Pa	3.35E+9 Pa	3.5E+9 Pa
   E2	1.5E+9 Pa	8.0E+10 Pa	6.9E+10 Pa	3.5E+9 Pa	3.35E+9 Pa	3.5E+9 Pa
   E3	1.5E+9 Pa	8.0E+10 Pa	6.9E+10 Pa	3.5E+9 Pa	3.35E+9 Pa	3.5E+9 Pa
   G12	1.5E+9 Pa	3.3E+10 Pa	2.8E+10 Pa	1.3E+9 Pa	1.24E+9 Pa	1.3E+9 Pa
   G13	1.5E+9 Pa	3.3E+10 Pa	2.8E+10 Pa	1.3E+9 Pa	1.24E+9 Pa	1.3E+9 Pa
   G23	1.5E+9 Pa	3.3E+10 Pa	2.8E+10 Pa	1.3E+9 Pa	1.24E+9 Pa	1.3E+9 Pa
   NU12	0.20	0.20	0.36	0.35	0.35	0.35
   NU23	0.20	0.20	0.36	0.35	0.35	0.35
   NU31	0.20	0.20	0.36	0.35	0.35	0.35
   A1	-5.5E-7 /°C	4.9E-6 /°C	-5.0E-6 /°C	5.3E-5 /°C	5.8E-5 /°C	5.3E-5 /°C
   A2	1.0E-5 /°C	4.9E-6 /°C	4.1E-5 /°C	5.3E-5 /°C	5.8E-5 /°C	5.3E-5 /°C
   A3	1.0E-5 /°C	4.9E-6 /°C	4.1E-5 /°C	5.3E-5 /°C	5.8E-5 /°C	5.3E-5 /°C