Accession Number : ADA018745

Title :   Reliability and Risk Assessment Methods for Redundant Structures.

Descriptive Note : Final rept. Jun 72-May 74,


Personal Author(s) : Orringer,O. ; McCarthy,J. F. ; Peterson,R. M. ; Seppanen,K. J.

Report Date : OCT 1975

Pagination or Media Count : 219

Abstract : This report summarizes developments of new reliability analysis methods resulting from research under Air Force Contract F33615-70-C-1131. The historical background of risk assessment activities concerning the USAF fleet is reviewed and the flaw-growth and wear-out approaches to material behavior are discussed to place the present work in perspective. A new definition of two categories of risk assessment probability calculation is proposed. The second category, which estimates risk due to strength degradation in an aging structure, is shown to require accounting for mechanical redundancy if accurate assessments are to be made. A new probability modelling procedure is presented. The new procedure accounts for mechanical redundancy by combining a new generalization of Daniels' fiber bundle theory with matrix structural analysis methods. Several example analyses are presented. The results of some related preliminary investigations on the effects of complexity in components and application of redundant models to time-to-failure calculations are discussed. (Author)

Descriptors :   *Reliability, *Redundant components, *Structural members, *Airframes, Structures, Risk, Failure(Mechanics), Assessment, Probability density functions, Strength(Mechanics), Degradation, Aging(Materials), Mathematical models, Safety, Fatigue(Mechanics), Life expectancy, Wear, Defects(Materials), Crack propagation, Overload, Loads(Forces), Probability, Wings, SKin(Structural), Jet fighters, Jet bombers

Subject Categories : Bombers
      Attack and Fighter Aircraft
      Mfg & Industrial Eng & Control of Product Sys

Distribution Statement : APPROVED FOR PUBLIC RELEASE