A one-dimensional transient thermal model has been developed to predict the thermal response of a decomposing, expanding polymer composite exposed to high temperatures. Both the decomposition and thermochemical expansion, as well as the storage of decom position gases in the solid material were considered in the formulation of the model. The accuracy of the model was evaluated by comparing predicted and experimental tempera ture profiles for a widely used glass-filled phenolic. The predicted temperatures agreed with the measured values with an average difference of 15.7°C and a standard deviation of 36.9°C.

Abstract.A numerical study of the thermally-induced response of two similar decomposing, expanding glass-filled polymer composites has been conducted. The study was performed using a newly developed numerical model, the accuracy of which was established by comparing predicted and experimental temperature profiles for one of the composites of interest. The results of the study were used to evaluate the effects of composition and processing history on the response of the materials.

A new impulse mechanical spectrometer to measure mechanical damping of filaments is described and first experimental results are briefly reported. The time-domain spectrum of a free decay induced by a light impulse mechanical excitation is analyzed by a laser beam diffraction technique and numerical analysis of the data. This technique is successfully used to measure the logarithmic decrement, d , and the resonant frequency, o f , of a bar filament sample fixed at one end.

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