Effect of Degradation of Material Properties on the Dynamic Response of Large Space Structures

The effect of degradation of material properties on structural frequencies and mode shapes of large space structures (LSS) is investigated herein. The difficulty and cost of maintenance of LSS require that these structures be designed to operate with a certain amount of load-induced damage. This damage is commmonly observed in fibrous composite media. Sensitivity studies conducted on representative space truss structures indicate that degradation of material properties will result in a reduction of natural frequencies and may have significant effects on the structural mode shapes. For even small amounts of stiffness reduction (10%), nodal locations may change significantly. It is clear that these effects mut be taken into consideration when designing control systems for large space structures.