The surface stiffness describes the relation between the load acting on the surface and the elastic deformation of the surface. The stiffness of the surface depends on the material (elastic modulus, shear modulus, Poisson's ratio) as well as on the geometry (for example, length, width, height).
In general, a distinction is made between the following relative stiffnesses:
- Bending stiffness
- is the torsional stiffness,
- Shear stiffness
- is the strain stiffness,
Furthermore, the surface stiffness is influenced by the thickness parameters.
Stiffness Types in RFEM
- Standard (isotropic surface)
- Without thickness (surface will be ignored in the calculation, necessary for solids)
- Rigid (surfaces with very high stiffness)
- Membrane (surfaces with membrane stiffnesses only)
- Without membrane tension (like Standard but failure of membrane stiffness under tension)
- Load transfer (a surface without stiffness, for applying surface load)