materiaalfunctie

Materiaalfunctie, commonly referred to in English as a material function, is a constitutive relation in continuum mechanics that describes how a material responds to external stimuli. It links state variables such as stress, strain, temperature, loading rate, and internal variables related to the material’s microstructure. The function serves to close the balance equations that govern motion, deformation, and heat transfer, allowing predictions of how a material will behave under given conditions.

Constitutive models can be explicit, expressing stress directly as a function of strain (and possibly strain rate and temperature), or implicit, defined through energy potentials or yield criteria. Examples range from simple linear elasticity, where stress equals a stiffness tensor times strain, to more complex behaviors including viscoelasticity, plasticity, and viscoplasticity. The choice of materiaalfunctie reflects material class, temperature, loading rate, and the material’s history.

Material functions can be local, depending only on the current state, or nonlocal, incorporating spatial interactions. They may be isotropic or anisotropic, capturing material symmetry or directional dependence. Derivation typically involves experiments, micromechanical reasoning, and sometimes multiscale considerations. In practice, these functions are calibrated to reproduce observed responses and implemented in numerical methods such as finite element analysis to predict stresses, deformations, and failure under operational loadings.

See also: constitutive model, material property, continuum mechanics, plasticity, viscoelasticity.