This paper discusses the measured damping characteristics of a three bay truss that uses pinned joints and how gravity loads can influence the damping in the truss joints. A clevis/tang joint design was used. Pinned joints normally have a small amount of clearance between the pins and the clevis/tang fittings. This clearance or gap allows a deadband region to be present in the force vs. displacement relationship of a strut. The small gap causes very significant changes in the dynamics and damping of a truss structure, particularly when the joint can traverse the deadband region. Gravity induced preloads in a truss can prevent a joint from traversing the deadband region of a joint. This paper describes test results from ground tests performed at Utah State University and flight tests performed on NASA's low-g aircraft and aboard the Space Shuttle. The flight tests provide a microgravity environment and the results were compared with the ground test results. The data suggests that damping is greatly influenced by the presence of gravity, the orientation of the gravity vector with respect to the truss, and the presence and size of the gap in the pinned joints.
Measured influence of gravity on the dynamic behavior of a truss using pinned joints
Messung des Schwerkrafteinflusses auf das dynamische Verhalten eines Fachwerkes mit Gelenkknotenpunkten
1996
11 Seiten, 24 Bilder, 6 Quellen
Aufsatz (Konferenz)
Englisch
Measured Influence of Gravity on the Dynamic Behavior of a Truss Using Pinned Joints
British Library Conference Proceedings | 1996
|Influence of Pinned Joints on Damping and Dynamic Behavior of a Truss
Online Contents | 1995
|