An ensemble of fibre waviness profiles are generated from an assumed spectral density of waviness using the Monte Carlo method. The compressive strength for each fibre waviness profile is calculated directly by the finite element method. The statistical distribution of compressive strength for an ensemble of fibre waviness profiles has also been examined. It is found that the probability distribution of strength is well matched by a Weibull fit, and the dependence of the Weibull parameters upon the spectral density of waviness is ascertained. It is concluded that the strength depends mainly upon the degree of waviness, as parameterized by the root mean square, with only a minor role played by the shape of the power spectral density function.
Good agreement is observed between the predicted and measured distribution of strength.
Finally, the failure modes of composite sandwich beams with a PVC foam core are reviewed for end compression, and 4-point bending. The operative failure modes include macrobuckling of the beam, microbuckling of the face sheets, core shear and indentation. Failure mode maps are constructed and minimum weight designs are determined as a function of appropriate structural load index. Handicapper accommodations may be requested by calling the Department of Materials Science and Mechanics, 355-5141, at least one day prior to the seminar. Requests received after this date will be met when possible.