Initial Dynamic Load Estimates During Configuration

Dynamic analysis of aerospace systems is required to insure that the structures will maintain their integrity and provide predictable and acceptable mechanical performance throughout the mission profile of specified acceleration environments. This analysis includes the structural response to shock and vibration and evaluates the maximum deflections and material stresses and the potential for the occurrence of elastic instability, fatigue and fracture. The required computations are often performed by means of finite element analysis (FEA) computer programs in which the structure is simulated by a finite element model which may contain thousands of elements. The formulation of a finite element model can be time consuming, and substantial additional modeling effort may be necessary if the structure requires significant changes after initial analysis. This paper presents rapid methods for obtaining rough estimates of the structural response to shock and vibration, for the purpose of providing guidance during the intial mechanical design configuration stage.