Your issue of getting zero reaction force (RF3) in the impactor's reference point could be due to several reasons. Here are some troubleshooting steps to help you resolve it:

1. Check Contact Definition

• Ensure that the surface-to-surface contact is properly defined: The master surface should be the rigid impactor. The slave surface should be the composite plate. Use "Hard Contact" for normal behavior and "Penalty" for tangential behavior.

2. Verify Reference Point and Mass Definition

• Make sure the reference point is correctly assigned to the impactor.
• Check if the mass is properly assigned at the reference point:*MASS, NSET=ReferencePoint total_mass_value
• If the impactor is a discrete rigid body, check that the reference point is used for mass definition.

3. Check Impact Conditions

• Ensure the initial velocity is correctly applied at the reference point.
• Confirm that the impactor is actually making contact with the composite surface.
• Plot the displacement history of the impactor’s reference point to see if it moves as expected.

4. Review History Output Requests

• Ensure that RF3 is requested for the reference point:*OUTPUT, HISTORY *NODE OUTPUT, NSET=ReferencePoint RF3
• Also, check CF3 (Contact Force in Z direction) as an alternative.

5. Check Interaction Properties

• If contact is defined but the surfaces are not actually in contact at impact, increase the contact stiffness.
• Use "Adjust contact initialization" to ensure proper initial contact.

6. Verify Step Definition

• Ensure that the step is dynamic explicit and the time increment is small enough to capture the impact.

Next Steps