# Introduction

The purpose of behaviour bricks is to hide (by default) part of the behaviour implementation. In other word, they are meant to create a context which simplifies the implementation of some specific behaviours’ classes.

The easiest way to introduce behaviour bricks is to shortly describe the example of the StandardElasticity brick. This brick applies to strain based mechanical behaviours. It assumes:

• that the total strain is split in an elastic part and a inelastic part.
• that the stress are related to the elastic strain through the Hooke law.
• that the total strain only appears in the equation associated with the split of the strain.

With those assumptions, the StandardElasticity brick can automatically provide:

• Automatic computation of the stress tensor at various stages of the behaviour integration.
• Automatic computation of the consistent tangent operator.
• Automatic support for plane stress and generalized plane stress modelling hypotheses (definitions of the axial strain as an additional state variables and the associated equation enforcing the plane stess condition).
• Automatic addition of the “standard” terms associated with the elastic strain state variable.

# The @Brick keyword

## Syntax

The @Brick keyword introduces a behaviour brick. It is followed by the name of the brick. This name can be given as a string.

## Example

@Brick "StandardElasticity"{
young_modulus: 150e9,
poisson_ratio: 0.3
};

# List of available bricks

The following brick are available:

• the StandardElasticity brick, which has been described in the introduction of this page. In practice, the evolution of MFront and the development of the StandardElastoViscplasticity brick, has made the StandardElasticity brick a kind of special case of the StandardElastoViscoplasticity where the stress potential is limited to the Hooke’ one and no inelastic flow is allowed. As such, most information concerning the StandardElasticity brick can be found on the page dedicated to the Hooke stress potential. In particular, all options passed to the StandardElasticity brick are indeed forwarded to the underlying Hooke stress potential.
• the DDIF2 brick
• the StandardElastoViscoplasticity brick
• FiniteStrainSingleCrystal