Fault tree analysis for composite structural damages

Abstract

Composite airframes suffer from complex damage modes during operation. Many investigations tend to look into specific aspects of damage mechanisms but seldom take a systematic view. This paper introduces a new fault tree methodology to synthesize various damage modes of composite structures by identifying possible damage causes. Qualitative analysis is performed incorporating structure importance analysis, probability importance analysis and relative probability importance analysis. Quantitative analysis by Monte Carlo simulation is then conducted as a validation to demonstrate the feasibility of the fault tree for composite damages. A number of options addressing main damage causes are proposed to improve the reliability of composite structures. Engineers from airlines and manufacturers can use this method to prioritize the main damage causes in different situations as a failure preventative tool or damage evaluation. Also, this approach can be extended to provide valuable inputs to other advanced methodologies to perform better diagnosis and prognosis for composites.