Simple Failure Model Reference

The Simple Failure model emulates bonds that fail instantaneously under load.

This model has applications such as:

Oil and gas drilling, where the rock surface is represented by particle clumps and repeated passes of the drill cause cumulative damage.
Pharmaceutical tablet manufacture, where tablets are formed from compressed powder and the strength of internal bonds, predicting breakage resistance, can be predicted from force and time of compression.
Mowing and harvesting, and bulk properties of polymers, where breakable fibers are represented by Flexible Fiber particles in conjunction with the Simple Failure model.

If the tensile or shear stresses between particles exceeds the maximum limits, the bond breaks and the particles separate. Thereafter, the other selected Phase Interaction models determine the particle-particle interaction upon collision.

If neither Simple Failure nor Constant Rate Damage is selected, the bonds between particles are treated as unbreakable.


Theory	See Simple Failure Model.
Provided By	[physics continuum] > Models > Multiphase Interaction > Phase Interactions > Phase Interaction [n] > Models > Optional Models
Example Node Path	Continua > Physics 1 > Models > Multiphase Interaction > Phase Interactions > Phase Interaction 1 > Models > Simple Failure
Requires	Under Lagrangian Multiphase, select Particle Type: DEM Particles Under Multiphase Interaction: Select Phase Interaction Topology: DEM Phase Interaction if it has not been automatically selected. Set the First Phase and Second Phase properties of DEM Phase Interaction to DEM Lagrangian phases. Select Optional Models: Hertz Mindlin, Walton Braun, or Linear Spring Optional Models Parallel Bonds or Bonded Particles are not required if the Flexible Fiber model is selected under Lagrangian Phase Models.
Activates	Model Controls (child nodes)	Bond Tensile Strength, Bond Shear Strength
	Field Functions	Bond Damage, Bond Shear Strength, Bond Tensile Strength. See Discrete Element Method Field Function Reference.

Bond Tensile Strength

Specifies the methods for assigning and updating maximum tensile strength $δ_{max}$ for the bond. The bond fails if tensile stress $δ_{m}$ exceeds $δ_{max}$ in Eqn. (3292).

Method: No Failure (unbreakable bonds, the default) and the standard methods for a scalar profile are available for this value.
Dimensions: The dimensions of $δ_{max}$ , Stress. (Read only.)
Update option: When set to Initialize only, the maximum tensile stress $δ_{max}$ is defined when two particles form a bond and remains the same as long as the bond lasts. When Initialize and update is activated, $δ_{max}$ is updated every sub-step according to the profile selected under Method.

Bond Shear Strength

Specifies the method for assigning and updating maximum shear strength to the bond. The bond fails if shear stress $σ_{m}$ exceeds $σ_{max}$ in Eqn. (3293).

Method: No Failure (unbreakable bonds, the default) and the standard methods for a scalar profile are available for this value.
Dimensions: The dimensions of $σ_{max}$ , Stress. (Read only.)
Update option: When set to Initialize only, the maximum tensile stress $σ_{max}$ is defined when two particles form a bond and remains the same as long as the bond lasts. When Initialize and update, $σ_{max}$ is updated every sub-step according to the profile selected under Method.