Practical Procedures for Reliability Estimation of Spacecraft Structures and Their Components

Abstract

The analysis of structural systems is mostly based on the assumption that the parameters are e xed, i.e., deterministic values. This contradicts the experience that the structural parameters often may vary (randomly) considerably. A way to model these uncertainties is to apply probabilistic methods. Two concepts are presented: The e rst is an engineering tool, which basically performs (weight-controlled ) Monte Carlo simulation strategies using the capabilities of highly developed e nite element programs, e.g., ASKA. A second concept is the stochastic e nite element method using random e elds that, combined with the response surface method, is a versatile tool to calculate the probabilities of failure. This approach is coded within the software package COSSAN, a tool for computational stochastic structural analysis. The feasibility of the concepts is presented using examples from spacecraft design, e.g., the ine uence of randomly distributed parameters on serviceability of devices mounted on satellites or the ine uence of randomly varying thickness on the reliability of an axially mounted fuel tank. Both concepts are shown to be practicable, especially for the design engineer.