Evaluation of the Three Parameter Weibull Distribution Function for Predicting Fracture Probability in Composite Materials
Master's thesis R.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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This thesis is an evaluation of the three parameter Weibull distribution function for predicting fracture in a composite material subjected to failure under both uniform and nonuniform stress distributions. The specific forms of the three parameter Weibull equations for these failure modes are derived for a general laminated composite and simplified for the special case of a unidirectional composite. An analysis into a parameter determination methodology which is mathematically reproducible is presented. The resulting expressions and methodology are applied to experimental bending, tension and three-point loading failure data for 0-degree and 90-degree unidirectionally laminated graphite-epoxy specimens. Weibull parameter sets are derived from both the bending and tension experimental data. Each set is then used to evaluate the theorys ability to predict the probability of failure throughout the three failure modes and thereby to establish a single set characteristic of the material. A characteristic set of values capable of predicting failure across the variety of failure modes was not found for this composite material.
- Laminates and Composite Materials
- Statistics and Probability