The program defines contact conditions between the body and the impact plane automatically. You can define contact conditions between faces of different components in an assembly. For component contact conditions, only Allow Penetration and Bonded (No clearance) are allowed. For local contact sets, the No penetration contact option is available in addition to the Allow Penetration and Bonded (No clearance) options.
Assembly components can detach from each other after impact depending on the contact forces that develop between them during the time of impact. Apply a No penetration contact condition at the regions where parts are not bonded to each other and are free to slide or detach. Assembly components cannot detach before impact.
Node-to-Node contact is not allowed in drop test studies.
Friction
You can specify a coefficient of friction:
- between the model and the impact plane (Drop Test Setup PropertyManager)
- between bodies with No penetration contact (Contact Sets PropertyManager)
Contact Damping
Contact damping is considered for bodies that come into contact with each other during impact and have No penetration contact between them. Contact damping is calculated as viscous damping. The input is a damping value as a ratio of the critical damping (ζcr = 2* m* ω).
The application of contact damping reduces the high frequency oscillations that may occur during impact and improves the solution stability (Drop Test Setup PropertyManager). The energy loss associated with this type of damping is through the contact interface only.
Energy Loss
Loss of energy occurs due to friction, damping, or plastic deformation (for von Mises plasticity materials).
If all materials are linear elastic and the coefficient of friction is set to zero, the impact causes no loss of energy and the model keeps bouncing indefinitely.