A Study of Joint Damping in Metal Plates
- Paper number
IAC-06-C2.3.10
- Author
Dr. Scott Walker, University of Southampton, United Kingdom
- Coauthor
Dr. Guglielmo Aglietti, University of Southampton, United Kingdom
- Coauthor
Dr. Paul R. Cunningham, United Kingdom
- Year
2006
- Abstract
The correct prediction of a spacecraft structural response to dynamic loads is crucial to assess its capability to withstand the launch environment. Many parameters are used to define the response of a structure, however the one that takes into account the dissipation of energy resulting in the decay of the vibration is the least understood and the most difficult to quantify. For satellite applications the determination of the correct dynamic behaviour and in particular the structural damping is also important to asses the vibration environment for the spacecraft subsystems and ultimately their capability to withstand the launch vibration environment. There is, however, only a limited knowledge of how the joints in the structure affect the damping of the complete structure. The object of this investigation is to experimentally analyse a range of aluminium panel configurations to study the affect of joints on the damping of the complete structure. This paper begins with a full description of the experimental method used to accurately determine the modal loss factors for each of the panel configurations analysed. Seven different panels were used in the experimental tests, six of which incorporate lap joints variations. The joint parameters investigated include fastener type, bolt torque, fastener spacing, overlap distance and the affect of stiffeners. The panels were freely suspended and excited at the anti node locations using the pendulum mounted impact hammer. One tear drop accelerometer was used to capture the resultant accelerations at four locations. The loss factors were determined directly from a sonograph of the vibration data, which plots decay time against frequency allowing the gradient of the decay to be determined. The damping results of eight different joint variants are presented for each of the first twelve modes of vibration. This data is directly compared to the damping factors for a monolithic panel. Various specific conclusions are made with respect to each of the joint parameters investigated. However, the primary conclusion is that the mode shape combined with the joint stiffness can be suggestive as to the likely magnitude of the modal loss factor.
- Abstract document
- Manuscript document
IAC-06-C2.3.10.pdf (🔒 authorized access only).
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