Results of force-state mapping tests to characterize struts using pinned joints

This paper discusses results of force-state mapping tests applied to truss struts which utilize a pinned joint. A clevisltang joint design was used. Pinned joints normally have a small amount of clearance between the pins and the clevisltang fittings. The small gap can cause very significant changes in the dynamics and damping of a truss structure, particularly when the joint can traverse the deadband region. Test results demonstrate that significant rebounding occurs each time a joint traverses the deadband region. Developing a force-state map from the test results becomes more difficult. This impacting phenomenon is shown to be greatly influenced by the conditions of the test bed. The behavior of a strut in the test bed can be significantly different than the behavior in a truss structure. The results of the force-state mapping technique are potentially of a more qualitative nature for this situation.