
Accession Number : ADA288343
Title : Life Prediction Methodology for Composite Laminates. Part 1. Constant Amplitude and TwoStress Level Fatigue.
Descriptive Note : Interim rept. 15 Jan 9330 Aug 94,
Corporate Author : WRIGHT LAB WRIGHTPATTERSON AFB OH
Personal Author(s) : Schaff, Jeffery R. ; Davidson, Barry D.
PDF Url : ADA288343
Report Date : SEP 1994
Pagination or Media Count : 45
Abstract : A strengthbased wearout model is presented for predicting the residual strength and life of composite laminates subjected to constant amplitude or twostress level fatigue loadings. It is assumed that the laminate undergoes proportional loading, that its residual strength is a monotonically decreasing function of the number of loading cycles, and that the probability of failure after an arbitrary number of cycles may be represented by a two parameter Weibull function. The model also incorporates a "cycle mix factor" to account for the degradation of strength and life that may be associated with frequent changes in the stress amplitude of the loading. Experimental results from twostress level loadings are used to evaluate the model's predictive capability for sequencing effects, as in a lowhigh or highlow test, and for cycle mix effects, as in a lowhighlowhigh repeating test. Good correlation between theory and experiment is obtained for all loadings and laminates studied.
Descriptors : *LAMINATES, *SHEAR STRESSES, *WEAR, TEST AND EVALUATION, MATHEMATICAL MODELS, WEIBULL DENSITY FUNCTIONS, DEGRADATION, PREDICTIONS, PARAMETERS, COMPOSITE MATERIALS, PROBABILITY, FAILURE, STRENGTH(MECHANICS), CYCLES, RESIDUALS, RESIDUAL STRESS.
Subject Categories : Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE