Damage Initiation Laws

Introduction

Damage initiation laws are used in softening materials to initiate the damage process. Each law defines a failure envelope in stress space. Once the current stress state reaches the envelop, the damage process begins. The normal to the failure envelop defines the normal to the plane of damage that is initiated. After initiation, damage propagates, but the damage initiation law is no longer used.

Damage initiation laws are currently only available in OSParticulas.

Define a Damage Initiation Laws

You create a damage initiation law using an Initiation material property within a Material command block. You pick the law by name or ID. After picking the law, all its properties are set using property commands within the same material definition. Refer to each damage initiation law type to learn about its failure envelope and about its required properties.

Damage Initiation Law Materials

This table lists the available damage initiation law. Click each one for more details and information on their properties.

Name	ID	Description
IsoFailure	1	Damage initiates in isotropic materials when principle stress exceeds tensile strength or when a maximum shear stress exceeds the shear strength. This law also accounts for pressure dependent shear and coupling between various direction (formerly call "MaxPrinciple", which can still be used).
TIFailure	2	Damage initiates when axial stress exceeds axial tensile strength, axial shear stress exceeds axial shear strength, principle stress in the transverse plane exceeds transverse shear strength, or maximum shear stress in transverse plane exceeds the shear strength.
OrthoFailure	3	Damage initiates when axial stress or shear stress in each of three material symmetry planes exceed the material strength in that direction.

It is relatively easy to write code for new damage initiation laws, if needed.