2 5 7 31 41
- --- -- ---- -------------------- --------- ---------
|X| | |FEND|XXXXXXXXXXXXXXXXXXXX| |XXXXXXXXX|
- --- -- ---- -------------------- --------- ---------
| | | |
| | | |
| | | (1) Size (E10.0)
| | |
| | |
| | | 51 61 71
| | | --------- --------- ---------
| | | | |XXXXXXXXX| |
| | | --------- --------- ---------
| | | | |
| | | | |
| | | | (3) Damping coefficient (E10.0)
| | | |
| | | (2) Friction coefficient (E10.0)
| | |
| | |_Compulsory Data Record Keyword (A4)
| |
| |_Optional User Identifier (A2)
|
|_Compulsory END on last data record in Data Category (A3)
(1) The size of the fender is the distance between the contact planes at which the fender just touches both of them.
(2) This is the friction coefficient μ. The friction force is given by F = μR, where R is the normal reaction. See note below.
(3) Material (or structural) damping coefficient β. Damping is modeled as linear material damping, where the damping coefficient is (β)(stiffness). Damping is only applied in the direction perpendicular to the contact points.
Note: Fender friction works best in situations where the friction force is smaller than other forces in the same direction. Friction will slow down relative motion between two structures, but is not suitable for keeping them fixed together - there is no "stiction". When the relative velocity changes sign the friction force must also change sign, but to avoid an instantaneous change in force (and therefore an instantaneous change in acceleration) a smoothing function is applied. This means that when the relative velocity is very small the friction force is also small, and the structures can move relative to each other.