Membrane property definition
- @MEMBRANE_PROPERTY_DEFINITION {
- @MEMBRANE_PROPERTY_NAME {MbnPropName} {
- @THICKNESS_PROPERTY_NAME {ThickPropName}
- @YOUNG'S_MODULUS {E}
- @POISSON'S_RATIO {ν}
- @STIFFNESS_MATRIX_A {a_{1}, ...a_{9}}
- @MATERIAL_DENSITY {ρ}
- @DAMPING_COEFFICIENT {μ_{s}}
- @COMMENTS {CommentText}
- }
NOTES
- The thickness distribution of the surface of the membrane is defined by the thickness property, ThickPropName.
- The physical mass and stiffness properties of a membrane are defined in this section. The mass properties are computed from the material density, ρ.
- In general, the stiffness characteristic of a membrane can be represented in the following matrix form N = A ε, where N^{T} = {N_{c3}, N_{22}, N_{12}} is the vector of in-plane forces per unit length of the membrane and ε^{T} = {ε_{c3}, ε_{22}, ε_{12}} the corresponding in-plane strains. All loading and strain quantities are measured in a material frame of reference. The thickness of the membrane is allowed to vary over the surface that defined the membrane. 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 membrane according to the keyword appearing next.
- @YOUNG'S_MODULUS: the membrane is assumed to be made of an isotropic, linearly elastic material. The stiffness matrix will be computed from the Young's modulus, E and Poisson's ratio, ν.
- @STIFFNESS_MATRIX_A: the membrane is assumed to be made of an anisotropic, linearly elastic material. The stiffness matrix will be computed from constants .
- Damping in the membrane can be modeled by viscous forces N_{d}^{*} proportional to the strain rates, N_{d}^{*} = μ_{s} A dε^{*}/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.