PCOMP

Bulk Data Entry Defines the structure and properties of an n-ply composite laminate material.

Attention: Valid for Implicit and Explicit Analysis

Format - Implicit


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
PCOMP	`PID`	`Z0`	`NSM`	`SB`	`FT`	`TREF`	`GE`	`LAM`
	`MID1`	`T1`	`THETA1`	`SOUT1`	`MID2`	`T2`	`THETA2`	`SOUT2`
	`MID3`	`T3`	`THETA3`	`SOUT3`	etc.
	`DS`	`NRPT`

Format - Explicit


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
PCOMP	`PID`	`Z0`	`NSM`	`SB`				`LAM`
	`MID1`	`T1`	`THETA1`	`SOUT1`	`MID2`	`T2`	`THETA2`	`SOUT2`
	`MID3`	`T3`	`THETA3`	`SOUT3`	etc.
	`EXPLICIT`	`ISOPE`	`HGID`	`NIP`

Example


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
PCOMP	100	-0.5		1.E5	STRN	100.
	120	0.2	0.0	YES	120	0.6	0.0	NO
	120	0.2	0.0	YES
	1.0

Definitions


Field	Contents	SI Unit Example
`PID`	Unique composite property identification. Integer Specifies an identification number for this property. <String> Specifies a user-defined string label for this property. 2 No default (Integer > 0 or <String>)
`Z0`	Real number or character input (Top/Bottom). Real Number Represents the distance from the shell element reference plane to the bottom surface of the shell. Default = -0.5 * Thick, Thick being the composite total thickness (Real or blank) Character Input 17
`NSM`	Nonstructural mass per unit area. No default (Real)
`SB`	Allowable inter-laminar shear stress (shear stress in the bonding material). Disregarded if blank or 0.0. No default (Real ≥ 0.0)
`FT`	Failure theory code. If blank, no failure calculations are performed. The following failure theory codes are supported: HILL Hill Theory HOFF Hoffman Theory TSAI Tsai-Wu Theory STRN Maximum Strain Theory STRS Maximum Stress Theory HASH Hashin Criteria PUCK Puck failure Criteria See Comments 13 14 15 18. Default = no failure calculations are performed
`TREF`	Reference (stress free) temperature. 1 Default = 0.0 (Real)
`GE`	Damping coefficient. 10 11 USEMAT Use `GE` from ply material data to calculate damping. Default = 0.0 (Real)
`LAM`	Laminate option. If blank, all plies must be specified and all stiffness terms are developed. The following options are supported: SYM Only plies on the bottom half of the composite lay-up needs to be specified. These plies are automatically symmetrically reflected to the top half of the composite and given consecutive numbers from bottom to top. MEM All plies must be specified, but only membrane terms `MID1` are developed. `Z0` is ignored (assumed to be: -0.5* Thick). BEND All plies must be specified, but only bending terms `MID2` are developed. `Z0` is ignored (assumed to be: -0.5* Thick). SMEAR All plies must be specified, stacking sequence is ignored, and `MID1` is set equal to `MID2` on the derived equivalent PSHELL, while `MID3`, `MID4`, TS/T, and 12I/T*3 are set to blank. `Z0` is ignored (assumed to be: -0.5 Thick). SMEARZ0 All plies must be specified, stacking sequence is ignored. While the laminate is still considered to be made of homogenized (smeared) material, the effect of offset `Z0` is taken into account. Hence, if `Z0` ≠ -0.5 * Thick, the equivalent PSHELL will include `MID1`, `MID2` and `MID4`. `MID3` is still set to blank, that is no transverse shear deformation is considered. SMCORE All plies must be specified. The last ply specifies core properties and the previous plies specify face sheet properties. The face sheet properties are calculated without regard for stacking sequence; half of the total face sheet thickness is then placed on top of the core, and half is placed on the bottom, to produce a symmetric laminate. Stiffness of the core is ignored while its density is included in inertia calculations. `Z0` is ignored (assumed to be: -0.5* Thick). SYMEM Only plies on the bottom half of the composite lay-up needs to be specified. These plies are automatically symmetrically reflected to the top half of the composite and given consecutive numbers from bottom to top. Only membrane terms are developed for the full laminate. `Z0` is ignored (assumed to be: -0.5* Thick). SYBEND Only plies on the bottom half of the composite lay-up needs to be specified. These plies are automatically symmetrically reflected to the top half of the composite and given consecutive numbers from bottom to top. Only bending terms are developed for the full laminate. `Z0` is ignored (assumed to be: -0.5* Thick). SYSMEAR Only plies on the bottom half of the composite lay-up needs to be specified. These plies are automatically symmetrically reflected to the top half of the composite and given consecutive numbers from bottom to top. Stacking sequence is ignored, and `MID1` is set equal to `MID2` on the derived equivalent PSHELL, while `MID3`, `MID4`, TS/T and 12I/T*3 are set to blank. `Z0` is ignored (assumed to be: -0.5 Thick). Default = blank, that is all plies must be specified
`MIDi`	Material IDs of individual plies. The plies are identified by consecutively numbering them from 1 at the bottom layer. The `MID`s must refer to MAT1, MAT2, MAT4, MAT5, or MAT8 Bulk Data Entries. If `MIDi` is not specified, default is the last defined `MIDi`. Default = last defined `MIDi` (Integer > 0 or blank, except that `MID1` must be specified)
`Ti`	Thicknesses of individual plies. If `Ti` is not specified, default is the last defined `Ti`. Default = last defined `Ti` (Real ≥ 0.0 or blank, except that `T1` must be specified)
`THETAi`	Orientation angle, in degrees, of the longitudinal direction of each ply relative to the x-axis of the material coordinate system associated with a given element. If no material coordinate system is specified for the element, the angle is measured relative to side 1-2 of this element. Default = 0.0 (Real or blank)
`SOUTi`	Stress, Strain and Failure Index output request for individual plies. 3 4 NO (Default) YES
`DS`	Design switch. If non-zero (1.0), the elements associated with this PCOMP data are included in the topology design volume or space. Default = blank (Real = 1.0 or blank)
`NRPT`	Number of repeat laminates 19 Default = blank (Integer > 0 or blank)
`EXPLICIT`	Flag indicating that parameters for Explicit Analysis are to follow.
`ISOPE`	Element formulation flag for Explicit Analysis. 20 21 22 BT Belytschko-Tsay. BWC (Default for four-noded CQUAD4 elements in explicit analysis) Belytschko-Wong-Chiang with full projection. blank
`HGID`	Identification number of the hourglass control (HOURGLS) entry. 23 24 Default = Blank (Integer > 0
`NIP`	Number of Gauss points through thickness. Default = 3 (1 ≤ Integer ≤ 10)

Comments

TREF specified on the PCOMP entry overrides reference temperatures given for individual ply materials. If TREF is not specified (blank) on the PCOMP card, then all the ply materials must have the same reference temperature.
String based labels allow for easier visual identification of properties, including when being referenced by other cards. (For example, the PID field of elements). For more details, refer to String Label Based Input File in the Bulk Data Input File.
Stress, Strain and Failure Index output for the PLY is activated by setting SOUT to YES. In addition, the I/O Options CSTRESS, CSTRAIN, and CFAILURE should be defined for Composite Stress, Composite Strain, and Failure Index output, respectively. Failure Index output also requires that the FT and SB fields be defined on the corresponding PCOMPP entry, and that stress/strain allowables (material strengths) on the referenced materials are defined.
An additional piece of information available with ply results is "failure index for the element," which is the maximum of failure indices for individual plies in this element. Only the plies with SOUTi set to YES are considered in the evaluation of this maximum.
If all plies specify zero transverse shear coefficients (G1Z, G2Z on MAT8 card, isotropic G for MAT1, not available for MAT2), the in-plane shear modulus will be used to determine transverse shear stiffness of the composite.
Note: If just one layer has a nonzero value specified for transverse shear modulus, this substitution is not being performed, and user-specified values are being used for all plies.
The signs given to stress limits for compression and tension (ST, SC, for MAT1; Xt, Xc, and so on for MAT8) are of no relevance. Absolute values are taken and used in the appropriate context to calculate failure indices.
For composites with offset (Z0 ≠ 0.5 * Thickness), correct values of shell stresses for the bottom and top surfaces of the shell are produced.
Note: These shell stresses are calculated using homogenized shell properties, and should be interpreted with caution.
Element GRID thicknesses cannot be defined for elements that reference PCOMP data.
Plies are listed from the bottom surface upwards, in respect to the element's normal direction.
Figure 1. (A) Stacking Sequence for a Non-symmetrical Laminate, (B) Stacking Sequence for a Symmetrical Laminate
If GE is specified on the PCOMP entry as a Real number, it will be used for the element, and the values supplied on material entries for individual plies are ignored. With USEMAT in this field, GE coefficients from ply material data will be used to calculate damping matrices for the composite. These matrices will, in general, be different for membrane, bending, and shear states.
To obtain the damping coefficient GE, multiply the critical damping ratio $C / C_{0}$ by 2.0.
For convenience, element output for the SMEAR and SMCORE options includes both homogenized shell stresses and individual ply stresses. However, because stacking sequence is ignored in these options, individual ply stresses will only be valid in cases of pure membrane deformation.
Hill's failure theory does not differentiate between compressive and tensile strength. While different values of respective strength limits are accepted, it is still recommended that Xt is set to be equal to Xc, and Yt is set to be equal to Yc when this criteria is used. Xt and Xc are allowable tensile and compressive stresses in the principle x direction of the material. Yt and Yc are allowable tensile and compressive stresses in the principle y direction of the material.
Failure index calculation according to Maximum Strain Theory is based on mechanical component of strain only, not on total strain. This is because only the mechanical strain contributes to actual damage of the respective ply (pure thermal expansion produces no damaging effects).
According to the formula, some failure criteria (for example, Tsai-Wu and Hoffman) would produce a negative ply failure, depending on the problem.
If PARAM, SRCOMPS,YES is added to the input file, strength ratios with respect to designated failure theory are output for composite elements that have failure indices requested.
The following two formats are permissible for the Z0 field:
Real Number:
It represents the distance from the shell element reference plane to the bottom surface of the shell (Default = -0.5 * Thick, Thick being the composite total thickness (Real or blank)).
Surface:
Top:
The shell reference plane, the plane defined by the grid points, and the top surface of the shell are coplanar.
This makes the effective "Real" Z0 value equal to the composite total thickness (-1.0 * Thick). See Figure 2.
Figure 2. Top option for Z0

Bottom:
The shell reference plane, the plane defined by the grid points, and the bottom surface of the shell are coplanar.
This makes the effective "Real" Z0 value equal to 0. See Figure 3.
Figure 3. Bottom option for Z0

Automatic offset control is available for ply thickness (size) optimization and for free-size optimization where the specified offset values are automatically updated, based on thickness changes. For free-size optimization, such an automatic offset is only applicable when Z0=0.0 or BOTTOM.
The material parameters, Xt, Xc, Yt, Yc, and S on the MAT8 Bulk Data Entry should be specified for failure criteria calculation.
The repeat laminates are added to the bottom of the current laminate. Output for repeat laminates are supported in OPTI, H3D, and PUNCH formats.
For CTRIA3 elements in explicit analysis, triangular shell formulation is automatically applied. Therefore, the definition of ISOPE has no effect on CTRIA3 elements in explicit analysis.
Both Belytschko-Tsay and Belytschko-Wong-Chiang shell formulations are very effective and robust. However, the performance of Belytschko-Tsay is poor, if the elements are warped. With Belytschko-Wong-Chiang formulation, the limitations in the element warpage are fixed with 20-30% additional computational cost.
The Belytschko-Tsay and Belytschko-Wong-Chiang shells do not possess stiffness in the normal rotational degree of freedom and this would lead to a singular stiffness matrix in case of implicit analysis. In explicit analysis, the unconstrained drilling degree of freedom usually does not create any difficulties since a stiffness matrix is not involved.
For four-noded quadrilateral elements in explicit analysis, hourglass control is required to avoid spurious zero-energy modes. Triangular elements do not require hourglass control.
When HGID is not specified, a default hourglass control is used.
This card is represented as a property in HyperMesh.