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*FRICTION

Keyword type: model definition, surface interaction

With this option the friction behavior of a surface interaction can be defined. The friction behavior is optional for contact analyses. There are no parameters.

The frictional behavior defines the relationship between the shear stress in the contact area and the relative displacement between the slave and the master surface. It is characterized by a linear range with tangent for small relative displacements (stick) followed by a horizontal upper bound (slip) given by , where is the friction coefficient and the local pressure (Figure 107). is dimensionless and usually takes values between 0.1 and 0.3, has the dimension of force per volume and should be chosen to be about 100 times smaller than the spring constant.

First line:

- *FRICTION

Following line for all types of analysis except modal dynamics:

- .
- .

Following line for modal dynamics:

- .
- .

    Example:

    *FRICTION
    0.2,5000.

defines a friction coefficient of 0.2 and a stick range slope of 5000 (assuming a static or dynamic procedure, but no modal dynamics).

Example files: friction1, friction2.

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