In engineering mechanics, stiffness is the resistance that an object can provide to elastic deformation due to external actions, such as forces or moments.
The stiffness depends on the following factors:
- Geometry of the object
- Material properties (modulus of elasticity, shear modulus)
In general, you can distinguish between specific types of stiffness, such as strain stiffness, torsional stiffness, and bending stiffness. Stiffnesses of a cross-section, for example, are specified in the cross-section properties.
The reciprocal value of the stiffness is the flexibility.