Shell Element Orthotropic Material Property Definition
Description: Defines the material property for an orthotropic material for isoparametric shell elements.
Format:
Example:
| Field | Definition | Type | Default | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MID | Material identification number. Referenced on a PSHELL or PCOMP entry only. | Integer > 0 | Required | ||||||||||
| E1 | Modulus of elasticity in longitudinal direction, also defined as the fiber direction or 1-direction. | Real ≠ 0.0 | Required | ||||||||||
| E2 | Modulus of elasticity in lateral direction, also defined as the matrix direction or 2-direction. | Real ≠ 0.0 | Required | ||||||||||
| NU12 | Poisson's ratio ( for uniaxial loading in 1-direction). Note that
 for uniaxial loading in 2-direction is related to
 , E 1, and E 2 by the relation
 .
|
Real | Required | ||||||||||
| G12 | In-plane shear modulus. | Real ≥ 0.0 or blank | 0.0 | ||||||||||
| G1Z | Transverse shear modulus for shear in 1-Z plane. | Real > 0.0 or blank | See Remark 2. | ||||||||||
| G2Z | Transverse shear modulus for shear in 2-Z plane. | Real > 0.0 or blank | See Remark 2. | ||||||||||
| RHO | Mass density. | Real or blank | 0.0 | ||||||||||
| Ai | Thermal expansion coefficient in i-direction. | Real or blank | 0.0 | ||||||||||
| TREF | Reference temperature for the calculation of thermal loads. | Real or blank | 0.0 | ||||||||||
| Xt, Xc | Allowable stresses or strains in tension and compression, respectively, in the longitudinal direction. Required if composite element failure index is desired. | Real ≥ 0.0 or blank | Default value for Xc is Xt | ||||||||||
| Yt, Yc | Allowable stresses or strains in tension and compression, respectively, in the lateral direction. Required if composite element failure index is desired. | Real ≥ 0.0 or blank | Default value for Yc is Yt | ||||||||||
| S | Allowable stress or strain for in-plane shear. | Real ≥ 0.0 or blank | 0.0 | ||||||||||
| GE | Structural element damping coefficient. See Remarks 7, 8, and 10. | Real or blank | 0.0 | ||||||||||
| F12 | Interaction term in the tensor polynomial theory of Tsai-Wu. Required if composite element failure index by Tsai-Wu theory is desired and if value of F12 is different from 0.0. See Remark 11. | Real | 0.0 | ||||||||||
| STRN | For the maximum strain theory only (see STRN in PCOMP entry). Indicates whether Xt, Xc, Yt, Yc, and S are stress or strain allowables. | Real = 1.0 for strain allowable | Blank for stress allowable | ||||||||||
| CS | Honeycomb sandwich core cell size. Required if material defines the core of a honeycomb sandwich and dimpling stability index is desired (LAM = HCS on the PCOMP entry). | Real ≥ 0.0 or blank | 0.0 | ||||||||||
| EC | Honeycomb sandwich core Young's modulus used for stability index analysis. | Real ≥ 0.0 or blank | See Remark 12 | ||||||||||
| GC | Honeycomb sandwich core shear modulus used for stability index analysis. | Real ≥ 0.0 or blank | See Remark 12 | ||||||||||
| ALPHA0 | Fracture angle for uniaxial transverse compression in degrees. Used in the NASA LaRC02 failure theory only (see LARC02 in PCOMP entry). See Remark 13. | 0.0 < Real < 90.0 | 53.0 | ||||||||||
| SB | Allowable inter-laminar shear stress of the composite laminate bonding material (allowable interlaminar shear stress). See Remark 14. | Real ≥ 0.0 or blank | See Remark 14 | ||||||||||
| EF1 | Modulus of elasticity of fiber. Used in the Puck PCP failure theory only (see PUCK in PCOMP entry). See Remark 15. | Real > 0.0 or blank | E1/0.6 | ||||||||||
| NUF12 | Poisson's ratio of fiber. Used in the Puck PCP failure theory only (see PUCK in PCOMP entry). | Real ≥ 0.0 or blank | 0.3 | ||||||||||
| MSMF | Mean stress magnification factor. Used in the Puck PCP failure theory only (see PUCK in PCOMP entry). See Remark 15. | Real ≥ 0.0 or blank | 1.1 | ||||||||||
| PNPT | Failure envelop slope parameter for transverse tension. Used in the Puck PCP failure theory only (see PUCK in PCOMP entry). See Remark 16. | Real ≥ 0.0 or blank | 0.35 | ||||||||||
| PNPC | Failure envelop slope parameter for transverse compression. Used in the Puck PCP failure theory only (see PUCK in PCOMP entry). See Remark 17. | Real ≥ 0.0 or blank | 0.3 | ||||||||||
| FT | Composite failure theory. The following theories are allowed:
|
Character or blank | |||||||||||
| NB | Allowable inter-laminar normal stress of the composite laminate bonding material (allowable interlaminar normal stress). See Remark 15. | Real ≥ 0.0 or blank | See Remark 15 | ||||||||||
| E3 | Modulus of elasticity in thickness direction, also defined as the matrix direction or 3-direction. See Remark 17. | Real > 0.0 | E2 | ||||||||||
| NU23 | Poisson's ratio ( for uniaxial loading in 2-direction). Note that
 for uniaxial loading in 3-direction is related to
 , E 2, and E 3 by the relation
 . See Remarks 17 and 18.
|
Real | 0.5 * E2/G2Z - 1 | ||||||||||
| NU31 | Poisson's ratio ( for uniaxial loading in 3-direction). Note that
 for uniaxial loading in 1-direction is related to
 , E 1, and E 3 by the relation
 . See Remarks 17 and 18.
|
Real | NU12 * E3/E1 | ||||||||||
| E1RSF | Longitudinal modulus of elasticity reduction scale factor for nonlinear composite Progressive Ply Failure Analysis (PPFA). See Remark 19. | 0.0 ≤ Real ≤ 1.0 | 1.0 | ||||||||||
| E2RSF | Lateral modulus of elasticity reduction scale factor for nonlinear composite Progressive Ply Failure Analysis (PPFA). See Remark 19. | 0.0 ≤ Real ≤ 1.0 | 1.0 | ||||||||||
| G12RSF | In-plane shear modulus reduction scale factor for nonlinear composite Progressive Ply Failure Analysis (PPFA). See Remark 19. | 0.0 ≤ Real ≤ 1.0 | 1.0 | ||||||||||
| G1ZRSF | Transverse shear modulus reduction scale factor in 1-Z plane for nonlinear composite Progressive Ply Failure Analysis (PPFA). See Remark 19. | 0.0 ≤ Real ≤ 1.0 | G12RSF | ||||||||||
| G2ZRSF | Transverse shear modulus reduction scale factor in 2-Z plane for nonlinear composite Progressive Ply Failure Analysis (PPFA). See Remark 19. | 0.0 ≤ Real ≤ 1.0 | G12RSF | ||||||||||
| TE1RSF | Identification number of a TABLES1 or TABLEST entry which defines the stress-strain relationship in the longitudinal direction for nonlinear composite Progressive Ply Failure Analysis (PPFA). | Integer ≥ 0 or blank | |||||||||||
| TE2RSF | Identification number of a TABLES1 or TABLEST entry which defines the stress-strain relationship in the lateral direction for nonlinear composite Progressive Ply Failure Analysis (PPFA). | Integer ≥ 0 or blank | |||||||||||
| TG12RSF | Identification number of a TABLES1 or TABLEST entry which defines the stress-strain relationship in the in-plane shear direction for nonlinear composite Progressive Ply Failure Analysis (PPFA). | Integer ≥ 0 or blank | |||||||||||
| TG1ZRSF | Identification number of a TABLES1 or TABLEST entry which defines the stress-strain relationship in the 1-Z plane for nonlinear composite Progressive Ply Failure Analysis (PPFA). | Integer ≥ 0 or blank | TG12RSF | ||||||||||
| TG2ZRSF | Identification number of a TABLES1 or TABLEST entry which defines the stress-strain relationship in the 2-Z plane for nonlinear composite Progressive Ply Failure Analysis (PPFA). | Integer ≥ 0 or blank | TG12RSF |
Remarks:
- The material identification number must be unique for all MATi entries.
- If test data is not available to accurately determine G1Z and G2Z, an approximate value is the in-plane shear modulus G12 which is used by default when PARAM, SHELLTVSMATTYPE is set to FLEXIBLE. When PARAM, SHELLTVSMATTYPE is set to RIGID, G1Z and G2Z will be penalty values which approximate a rigid transverse shear stiffness. (See Section 5, Parameters, for more information on SHELLTVSMATTYPE.)
- Xt, Yt, and S are required for composite element failure calculations when requested in the FT field of the PCOMP entry. Xc and Yc are also used but not required.
- MAT8 materials may be made temperature-dependent by use of the MATT8 entry. In STATIC solutions, linear elastic material properties will be updated as prescribed under the TEMPERATURE Case Control command.
- The mass density, RHO, will be used to automatically compute mass for all structural elements.
- Weight density may be used in field 9 if the value 1/g is entered on the PARAM, WTMASS entry, where g is the acceleration of gravity.
- To obtain the damping coefficient GE, multiply the critical damping ratio C/C0, by 2.0.
- TREF and GE are ignored if the MAT8 entry is referenced by a PCOMP entry.
- TREF is used only as the reference temperature for the calculation of thermal loads in linear solutions. If TEMPERATURE(INITIAL) is specified, TREF will be ignored.
- If PARAM, W4 is not specified, GE is ignored in transient response analysis. (See Section 5, Parameters, for more information on W4.)
- The interaction term F12 is experimentally determined from test specimens under biaxial loading. This inconvenience along with the constraint that F12 satisfy a stability criterion of the form
creates complications in the use of this theory. For this reason it is recommended that F12 be set to zero.
- The default value for EC is the minimum value of E1 and E2. The default value for GC is the average of G1Z and G2Z unless these values are zero in which case G12 is then used.
- The default value for ALPHA0 has been found experimentally and is typical for fiber reinforced polymer laminates. See the Autodesk Nastran User's Manual, Reference 5 for additional information.
- The allowable inter-laminar shear stress value SB corresponds to the top surface of the ply. The default value for SB is defined in the SB field of the PCOMP, PCOMPG, and PCOMPS entries and will be used when this field is blank.
- The allowable inter-laminar normal stress value NB corresponds to the top surface of the ply. The default value for NB is defined in the NB field of the PCOMPS entry and will be used when this field is blank.
- The default values for MSMF, PNPT, and PNPC are for carbon fibers. See the Autodesk Nastran User's Manual, Reference 13 and the table below for additional materials.
Variable Carbon Fiber Glass Fiber MSMF 1.10 1.30 PNPT 0.35 0.30 PNPC 0.30 0.25 - When the MAT8 entry is used without reference to a PCOMP layer composite property, the presence of E3, NU23, and NU31 specify that a plane strain formulation should be used. The default is plane stress. When the MAT8 entry is referenced on a PCOMP which requires E3, NU23, and NU31, they will be used if specified with the default values determined assuming transverse isotropy.
- Material stability requires that
If either condition is not met, a warning message will be issued.
- Recommended values for E1RSF, E2RSF, G12RSF, G1ZRSF, and G2ZRSF are shown in the below table.
Variable Recommended Value E1RSF 0.04 E2RSF 0.04 G12RSF 0.20 G1ZRSF 0.20 G2ZRSF 0.20