Materieparametere

Materieparametere, or material parameters, are the physical quantities that characterize how a material responds to external stimuli. They are used in constitutive models, experimental analysis, and numerical simulations to describe properties such as stiffness, strength, heat transfer, and electrical behavior.

They can be divided into categories: mechanical parameters (density, Young's modulus, Poisson's ratio, yield strength, hardening parameters), thermal parameters (thermal conductivity, specific heat, thermal expansion coefficient, diffusivity), electrical parameters (electrical conductivity, permittivity), magnetic parameters (permeability), and optical parameters (refractive index).

Parameter values depend on temperature, strain rate, microstructure, and history. They may be intrinsic to the material or depend on processing and treatment. In many cases a material exhibits anisotropy and must be described by tensors or direction-dependent functions.

Determination typically involves experiments (tension tests, compression, hardness tests, calorimetry, impedance spectroscopy) and inverse methods to identify parameters that best fit observed data. In practice, parameters are compiled into material models used in finite element analysis, computational materials science, and engineering design, often sourced from material data sheets or databases.

Limitations include variability between batches and the need to update parameters for new temperatures, loading rates, or damage states. Robust models include temperature- or rate-dependent evolution laws for parameters (hardening, damage).

See also: Constitutive models; Material science; Finite element method.