Abaqus Users - Pressure-Overclosure relationship
“Contact pressure-overclosure relationships,” Section .. helps to robustly find an approximate contact status distribution, and the goal of later iterations is. Figure “Softened” exponential pressure-overclosure relationship .. year old deck were utilized as the response goals of the corroded concrete. The input. In Abaqus the following contact pressure-overclosure relationships can be used to define the contact model. the “hard” contact relationship.
Specifying pressure-overclosure relationships for mechanical contact property options
They can be given as analysis data rather than incorporated directly into the subroutine, which means that the subroutine is simpler and does not have to be modified each time different coefficients are used.
User subroutine VFRIC cannot be used in conjunction with softened tangential behavior or with the general contact algorithm.
If p properties are specified, p data items should be given on the data line. User-defined, Number of state-dependent variables: Unsymmetric terms in the system of equations Friction constraints produce unsymmetric terms when the surfaces are sliding relative to each other.
These terms have a strong effect on the convergence rate if frictional stresses have a substantial influence on the overall displacement field and the magnitude of the frictional stresses is highly solution dependent. In many situations convergence can be improved if the effects of friction at a node are neglected in any increment during which the contact state changes from open to closed.
Errors caused by these assumptions will generally be small; however, if the contact zone changes rapidly as the analysis progresses, these errors can be significant and will sometimes slow or prevent convergence of the solution.
You can force friction at a node to be neglected in increments in which contact is established by delaying the application of friction to the increment.
This setting affects all friction models, including rough friction; however, it has no effect on user subroutine FRICwhich is called whenever contact occurs at the end of an increment. You can also toggle off Allow separation after contact if you want to prevent surfaces from separating once they have come into contact.Before The Person :: Relationship Goals (Part 1)
To specify these settings, select an option from the Constraint enforcement method list and do the following: Select Default to enforce constraints using a contact pressure-overclosure relationship. Select Augmented Lagrange Standard to enforce contact constraints using the augmented Lagrange method. If you select this option, specify the following additional settings from the Contact Stiffness options: From the Stiffness value field, either select Use default to have Abaqus calculate the penalty contact stiffness automatically or select Specify and enter a positive value for the penalty contact stiffness.
Contact pressure-overclosure relationships
Specify a factor by which to multiply the chosen penalty stiffness in the Stiffness scale factor field. Specify the Clearance at which contact pressure is zero. The default value is 0. Select the Penalty Standard constraint enforcement method to enforce contact constraints using the penalty method.
Contact pressure definition
From the Behavior field, either select Linear to use the linear penalty method for the enforcement of the contact constraint or select Nonlinear to use the nonlinear penalty method for the enforcement of the contact constraint. For more information, see Penalty method.
Specify the contact stiffness.
For the linear penalty method, specify the contact stiffness in the Stiffness value field.