Reliability Prediction and Cost Optimization for Composites Including Periodic Proof Tests in Service.
Abstract
An exploratory reliability analysis of composites under periodic proof tests in service is presented. The ultimate strength of composites is a random variable having a two-parameter Weibull distribution. A residual strength model is employed to describe the strength degradation of composites under service loads. Fatigue failure occurs as soon as the residual strength of composites is exceeded by service loads, such as gust turbulence for transport-type aircraft and maneuver loads for fighter aircraft. Both the gust and maneuver loads are considered as random loads and their exceedance curves obtained from field data are used in the present analysis. Meanwhile, the composites are subjected to periodic proof tests in order to eliminate weak components and to ensure an acceptable level of reliability. Taking into account all the random variables (ultimate strength and residual strength), strength degradations, service loads, proof tests and renewal processes, the probability of structural failure in service is derived. It is demonstrated by numerical examples that significant cost savings and reliability improvement for composite structures can be achieved by the application of the optimal periodic proof test.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 15, 1976
- Accession Number
- ADA040076
Entities
People
- Jann N. Yang
Organizations
- Virginia Tech