Life prediction methodology for composite laminates. Part 1. Constant amplitude and two-stress level fatigue. Interim report, 15 January 1993-30 August 1994
A strength-based wearout model is presented for predicting the residual strength and life of composite laminates subjected to constant amplitude or two-stress 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 two-stress level loadings are used to evaluate the model`s predictive capability for sequencing effects, as in a low-high or high-low test, and for cycle mix effects, as in a low-high-low-high repeating test. Good correlation between theory and experiment is obtained for all loadings and laminates studied.
- Research Organization:
- Wright Lab., Wright-Patterson AFB, OH (United States)
- OSTI ID:
- 76265
- Report Number(s):
- AD-A--288343/7/XAB; WL-TR--94-4046
- Country of Publication:
- United States
- Language:
- English
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