# PCOMPP

Bulk Data Entry Defines the properties of a composite laminate material used in ply-based composite definition.

## Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
PCOMPP PID Z0 NSM SB FT TREF GE
EXPLICIT ISOPE HGID NIP

## Example

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
PCOMPP 1 -0.1     HILL 20
EXPLICIT BWC 100 5

## Definitions

Field Contents SI Unit Example
PID Unique composite property identification number.

No default (Integer > 0)

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 11

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

Default = no failure calculations are performed

TREF Reference (stress free) temperature. 2

Default = 0.0 (Real)

GE Damping coefficient. 5 6
USEMAT
Use GE from ply material data to calculate damping.

Default = 0.0 (Real)

EXPLICIT Flag indicating that parameters for Explicit Analysis are to follow.
ISOPE Element formulation flag for Explicit Analysis. 13 14 15
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. 16 17

Default = Blank (Integer > 0

NIP Number of Gauss points through thickness.

Default = 3 (1 ≤ Integer ≤ 10)

1. The PCOMPP card is used in combination with the STACK and PLY cards to create composite properties through the ply-based definition.
2. TREF specified on the PCOMPP entry overrides reference temperatures given for individual ply materials. If TREF is not specified (blank) on the PCOMPP card, then all the ply materials must have the same reference temperature.
3. 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.
4. Element GRID thicknesses cannot be defined for elements that reference PCOMPP data.
5. If GE is specified on the PCOMPP 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.
6. To obtain the damping coefficient GE, multiply the critical damping ratio $C/{C}_{0}$ by 2.0.
7. 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.
8. 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).
9. According to the formula, some failure criteria (for example, Tsai-Wu and Hoffman) would produce a negative ply failure, depending on the problem.
10. 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.
11. 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 1.

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 2.

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.

12. The material parameters, Xt, Xc, Yt, Yc, and S on the MAT8 Bulk Data Entry should be specified for failure criteria calculation.
13. 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.
14. 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.
15. 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.
16. 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.
17. When HGID is not specified, a default hourglass control is used.
18. This card is represented as a property in HyperMesh.