SOLID185 is available in two forms:
Standard (nonlayered) structural solid (KEYOPT(3) = 0, the default) - see SOLID185 - 3D 8-Node Structural Solid.
Layered structural solid (KEYOPT(3) = 1) - see SOLID185 - 3D 8-Node Layered Solid.
| Matrix or Vector | Shape Functions | Integration Points | |
|---|---|---|---|
| Stiffness and Stress Stiffness Matrices; and Thermal Load Vector | Equation 11–217, Equation 11–218, and Equation 11–219 |
2 x 2 x 2 if KEYOPT(2) = 0, 2, or 3 | |
| Mass Matrix | Same as stiffness matrix |
2 x 2 x 2 | |
| Pressure Load Vector | Quad | Equation 11–70 and Equation 11–71 | 2 x 2 |
| Triangle | Equation 11–50 and Equation 11–51 | 3 | |
| Load Type | Distribution |
|---|---|
| Element Temperature | Trilinear thru element |
| Nodal Temperature | Trilinear thru element |
| Pressure | Bilinear across each face |
| Matrix or Vector | Shape Functions | Integration Points | |
|---|---|---|---|
| Stiffness and Stress Stiffness Matrices; and Thermal Load Vector | Equation 11–217, Equation 11–218, and Equation 11–219 |
In-plane: | |
| Mass Matrix | Same as stiffness matrix | Same as stiffness matrix | |
| Pressure Load Vector | Quad | Equation 11–70 and Equation 11–71 | 2 x 2 |
| Triangle | Equation 11–50 and Equation 11–51 | 3 | |
| Load Type | Distribution |
|---|---|
| Element Temperature | Bilinear in plane of element, linear thru each layer |
| Nodal Temperature | Trilinear thru element |
| Pressure | Bilinear across each face |
Structures describes the derivation of structural element matrices and load vectors as well as stress evaluations. General Element Formulations gives the general element formulations used by this element.
If KEYOPT(2) = 0 (not applicable to layered SOLID185), this
element uses
method (selective reduced
integration technique for volumetric terms) (Hughes([221]), Nagtegaal et al.([222])).
If KEYOPT(2) = 1 (not applicable to layered SOLID185), the uniform reduced integration technique (Flanagan and Belytschko([233])) is used.
If KEYOPT(2) = 2 or 3, the enhanced strain formulations from the work of Simo and Rifai([318]), Simo and Armero([319]), Simo et al.([320]), Andelfinger and Ramm([321]), and Nagtegaal and Fox([322]) are used. It introduces 13 internal degrees of freedom to prevent shear and volumetric locking for KEYOPT(2) = 2, and 9 degrees of freedom to prevent shear locking only for KEYOPT(2) = 3. If mixed u-P formulation is employed with the enhanced strain formulations, only 9 degrees of freedom for overcoming shear locking are activated.