Computational Models to Predict the Structural Reliability of Aerospace Systems

Abstract

Three case studies were presented in which computationalbased methodologies were used to assess structural reliability in the aerospace industry. The studies involved hotsection turbine disks of a helicopter engine, fan blades of a commercial airline engine, and bearings in an auxiliary power unit. In all cases, the results of the computational models were used to support the certification process for design and application changes. The statistical variation in design and usage parameters, including geometry, materials, speed, temperature, and other environmental factors, were considered. The response surface approach was used to construct a durability performance function. This performance function was used with the firstorder reliability method to determine the probability of failure and the sensitivity of the failure to the design and usage parameters. A hybrid combination of perturbation analysis and Monte Carlo simulation was used to incorporate timedependent random variables. System reliability methods were used to determine the system probability of failure and the sensitivity of the system durability to the design and usage parameters.