Orthotropic Plastic Softening Material

Constitutive Law

This MPM Material is an orthotropic, elastic-plastic material that can also develop anisotropic damage. The material is available only in OSParticulas.

In the absence of damage, this material is identical to a Anisotropic, Elastic-Plastic Material. In the absence of plasticity, this material is identical to an Orthotropic Softening Material. If conditions allow, the material can develop both plasticity and damage with softening. Note that if plastic yield properties are below damage initiation stress, the material may never reach stress to cause damage. But, if the plastic properties allow hardening, the material can yield first and then start damage after hardening allowing stresses to reach stress for initiation of damage.

Material Properties

For material properties, combine all options available for an Anisotropic, Elastic-Plastic Material and for an Orthotropic Softening Material. This material must, however, use large rotation mode.

Property	Description	Units	Default
(Orthotropic Properties)	Enter all properties needed to define the underlying orthotropic material response	varies	varies
(Orthotropic, Plastic Properties)	Enter orthotropic yield properties	varies	varies
(Orthotropic Softening Properties)	Enter properties for initiation of damage and for two softening laws	varies	varies
(other)	Properties common to all materials and must use the large rotation option	varies	varies

History Variables

The plasticity modeling for this material uses one history variable and will start with history variable number 1. After that variable, the remaining variables will be for the Orthotropic Softening Material material. Because plastic strain is used for plasticity, three additional history variables (compared to Orthotropic Softening Material) track the three components of cracking strains in the crack axis system corresponding to normal and shear crack opening displacements.

Let S be number of history variables for damage needed by an Orthotropic Softening Material, respectively. The history variables for this material are then:

• 1: Plastic law history variables
• 2 to 1+S: Orthotropic Softening Material history variables
• 2+S: ε_c,xx or x direction cracking strain normal to crack in the crack axis system
• 3+S: γ_c,xy or x-y direction shear cracking strain in the crack axis system
• 4+S: γ_c,xz or x-z direction shear cracking strain in the crack axis system

This material also tracks plastic strain which can be saved by using the plasticstrain archiving option. The total plastic is archived in the global axis system.

If you also archive the damagenormal, you will be able to plot a vector along the crack-opening displacement vector in the crack axis system.