Shell property definition
- @SHELL_PROPERTY_DEFINITION {
- @SHELL_PROPERTY_NAME {ShlPropName} {
- @YOUNG'S_MODULUS {E}
- @POISSON'S_RATIO {ν}
- @STIFFNESS_MATRIX_A {a_{1}, ...a_{9}}
- @STIFFNESS_MATRIX_D {d_{1}, ...d_{9}}
- @STIFFNESS_MATRIX_S {s_{1}, ...s_{4}}
- @MATERIAL_DENSITY {ρ}
- @MASS_PER_UNIT_AREA {m}
- @CENTRE_OF_MASS_LOCATION {x_{ cm}}
- @RADIUS_OF_GYRATION {ρ_{g}}
- @STIFFNESS_MATRIX_B {b_{1}, ...b_{9}}
- @STIFFNESS_MATRIX_F {f_{1}, ...f_{6}}
- @STIFFNESS_MATRIX_G {g_{1}, ...g_{6}}
- @DAMPING_COEFFICIENT {μ_{s}}
- @COMMENTS {CommentText}
- }
NOTES
- The physical mass and stiffness properties of a shell are defined in this section.
- The thickness of the shell is allowed to vary over the surface that defined the shell. Hence, the physical properties will be defined in a non-dimensional manner with respect to thickness.
- There are two ways of defining the stiffness properties of the cross-section according to the keyword appearing next.
- If the keyword @YOUNG'S_MODULUS appears first, the shell is assumed to be made of a homogeneous, isotropic, linearly elastic material. Young's modulus, E, and Poisson's ratio, ν, then completely define the material stiffness characteristics.
- If the keyword @STIFFNESS_MATRIX_A appears first, three stiffness matrices must be defined. Shells made of advanced composite materials with arbitrary lay-ups can be defined in this manner. The coupling stiffness matrices B, F, and G are assumed to vanish unless defined below.
- The mass characteristics of the shell are defined by three coefficients corresponding to integrals of the mass distribution through the thickness of the shell.
- There are two ways of defining the mass properties of the cross-section according to the keyword appearing next.
- If the keyword @MATERIAL_DENSITY appears first, the shell is assumed to be made of a homogeneous, linearly elastic material. The material density, ρ, then completely define the shell's mass characteristics.
- If the keyword @MASS_PER_UNIT_AREA appears first, the shell three mass coefficients are defined explicitly.
- When the shell is made of anisotropic material, elastic coupling can occur between the in-plane and bending behaviors (stiffness matrix B), in-plane and shearing behaviors (stiffness matrix F), or shearing and bending behaviors (stiffness matrix G). Any of these three matrices can be optionally defined.
- Damping in the shell can be modeled by viscous forces F_{d}^{*} proportional to the strain rates, F_{d}^{*} = μ_{s} C^{*} de^{*}/dt, where μ_{s} is the damping coefficient.
- It is possible to attach comments to the definition of the object; these comments have no effect on its definition.