A method of fabrication of a novel cellular composite structure has been devised based on a convoluted sheet of resin-impregnated fabric. The flexural properties of this structure with and without facings have been assessed in four point bending. In flexure the load deflection trace is linear up to a point at which a critical load is reached and the structure fails by a gradual buckling mechanism. The second moment of area of the structure's cross-section has been approximated to that of a square packed array of composite cylinders of equivalent dimensions and this successfully predicts beam properties. The effects of span and tube element geometry on flexural properties were studied to establish a method of predicting the mechanical response of a cellular composite beam in flexure. A failure criterion for the buckling of individual composite cylinders was applied to the cellular composite structure enabling a series of load versus deflection design curves to be drawn for any beam with any geometrical cross-section in any bending configuration. Future commercial prospects for the cellular structure have been anticipated by filing patent applications worldwide. Mechanical tests have been undertaken to establish the originality of the cellular material. The energy absorption capacity of the cellular composite structure was assessed. It was shown that the structure has an unusually high specific energy absorption capacity in comparison to single composite cylinders of equivalent geometric ratios. It was also demonstrated that the energy absorption, which is rate independent, is dependent on cell geometry and the orientation of the reinforcing fabric.
|Date of Award||1984|