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*SURFACE BEHAVIOR

Keyword type: model definition, surface interaction

With this option the surface behavior of a surface interaction can be defined. The surface behavior is required for any contact analysis. There is one required parameter PRESSURE-OVERCLOSURE. It can take the value EXPONENTIAL or LINEAR.

The exponential pressure-overclosure behavior takes the form in Figure 93. The parameters and define the kind of contact. is the contact pressure at zero distance, is the distance from the master surface at which the pressure is decreased to 1 % of . The behavior in between is exponential. A large value of leads to soft contact, a small value to hard contact.

The linear pressure-overclosure behavior (Figure 94) simulates a linear relationship between the pressure and the overclosure. At zero overclosure the pressure is zero as well. The user has to specify the slope of the pressure-overclosure curve and can specify a tension value for large clearances (should be small).

First line:

- *SURFACE BEHAVIOR
- Enter the parameter PRESSURE-OVERCLOSURE and its value.

Following line if PRESSURE-OVERCLOSURE=EXPONENTIAL:

- .
- .

Following line if PRESSURE-OVERCLOSURE=LINEAR:

- slope of the pressure-overclosure curve (must be positive).
- value for the tension at large clearances (default: 10/)

    Example:

    *SURFACE BEHAVIOR,PRESSURE-OVERCLOSURE=EXPONENTIAL
    1.e-4,.1

defines a distance of length units at which the contact pressure is .001 pressure units, whereas the contact pressure at loose contact is 0.1 pressure units.

Example files: contact1, contact2.

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