# Behavior laws and modeling: model concept

## Complexity of the laws

The materials utilized generally have an anisotropic, nonlinear, hysteretic behavior, and the corresponding material properties can also depend more or less strongly on other physical quantities, for example on temperature or frequency .

The behavior laws can therefore be very complex if we wish to get a very accurate representation of the materials.

## Consequence

Generally, it is not possible to express the complexity of a behavior law into one single model, which would simultaneously take into consideration the various aspects previously mentioned.

Indeed, in order to carry out the numerical simulation of a device with the given models of materials, one must take into consideration a certain number of requirements, such as:

- the possibility of evaluating all the model parameters within a reasonable time interval
- the possibility of carrying out the field computations utilizing these models, by the available numerical tools and within a reasonable time interval.

## The model concept

Therefore, the same material can be modeled in several ways, the choice depending on the studied phenomena and the operation conditions.