Built-in Contact Models

The contact models provided with PFC are listed in the table below. The models with “linear” in their keyword are referred to as Linear-Based Models. Bonded-particle models (BPMs) are constructed with the linear contact bond, linear parallel bond, soft bond, flat joint, subspring network, and smooth joint contact models.

• Null Model
• Linear Model
• Linear Contact Bond Model
• Linear Parallel Bond Model
• Soft-Bond Model
• Flat-Joint Model
• Smooth-Joint Model
• Subspring Network Model
• Spring Network Model
• Hertz Model
• Hysteretic Model
• Rolling Resistance Linear Model
• Adhesive Rolling Resistance Linear Model
• Burger’s Model
• Edinburgh-Elasto-Plastic-Adhesive (EEPA) Contact Model
• Johnson-Kendall-Roberts (JKR) Contact Model
• Mohr Model
• Linear Dipole Model
• FISH Model

Table 1: Built-in Contact Models

Keyword	Name	Behavior Summary
null	null	No mechanical interaction.
linear	linear	Linear elastic, frictional and viscous behavior.
linearcbond	linear contact bond	Linear model with contact bonding for BPM.
linearpbond	linear parallel bond	Linear model with parallel bonding for BPM.
softbond	soft bond	Linear softening bond model for BPM or granular applications.
flatjoint	flat joint	Finite-size, linear elastic and either bonded or frictional interface with partial damage for BPM.
smoothjoint	smooth joint	Provides a joint within a BPM.
subspringnetwork	subspring network	Rigid body spring network implementation with subcontacts for BPM.
springnetwork	spring network	Original rigid body spring network implementation.
hertz	hertz	Non-linear elastic, frictional and viscous behavior for granular applications including impact problems.
hysteretic	hysteretic	Similar to hertz model but for impact problems, directly specify normal restitution coefficient.
rrlinear	rolling resistance linear	Linear model and rolling-resistance mechanism for granular applications.
arrlinear	adhesive rolling resistance linear	Linear model, rolling-resistance mechanism, and adhesion to give a cohesive granular material.
burger	Burger’s	Provides a creep mechanism for granular applications.
eepa	EEPA	Edinburgh Elasto-Plastic Adhesive model for granular applications.
jkr	JKR	Johnson-Kendall-Roberts model for cohesive granular applications.
mohr	Mohr	Mohr model for joints.
lineardipole	linear dipole	Linear model with magnetic dipoles.
fish	FISH	Add custom physics with FISH as a contact model.

Linear-Based Models

The linear contact bond, linear parallel bond, rolling resistance linear, adhesive rolling resistance linear, and linear dipole contact models are denoted as linear-based models, because they include the behavior of the linear model. The properties consist of a Linear Group and a Dashpot Group, and these properties are identical for all of the linear-based models. The linear contact bond model adds a bonded behavior defined by the properties in its Contact-Bond Group. The linear parallel bond model adds a second interface to provide the bonded behavior defined by the properties in its Parallel-Bond Group. The rolling resistance linear model adds a rolling-resistance behavior defined by the properties in its Rolling-Resistance Group. The adhesive rolling resistance linear model adds both rolling-resistance and adhesive behaviors defined by the properties in its Rolling-Resistance and Adhesive Groups. The linear dipole model adds magnetic interactions defined by the properties in its Dipole Group.