FIBER-COMPOSITE THIN SHELLS SUBJECTED TO THERMAL BUCKLING LOADS

The results of parametric studies to assess the effects of various par ameters on the buckling behavior of angle-ply, laminated thin shells i n a hot environment are presented in this paper. These results were ob tained by using a three-dimensional finite element analysis. An angle- ply, laminated thin shell with fiber orientation of [theta/-theta]2 wa s subjected to compressive mechanical loads. The laminated thin shell has a cylindrical geometry. The laminate contained T300 graphite fiber s embedded in an intermediate-modulus, high-strength (IMHS) matrix. Th e fiber volume fraction was 55% and the moisture content was 2%. The r esidual stresses induced into the laminated structure during the curin g were taken into account. Parametric studies were performed to examin e the effect on the critical buckling load of the following parameters : cylinder length and thickness, internal hydrostatic pressure, differ ent ply thicknesses, different temperature profiles through the thickn ess of the structure, and different layup configurations and fiber vol ume fractions. In conjunction with these parameters the ply orientatio n varied from 0-degree to 90-degrees. Seven ply angles were examined: 0-degree, 15-degrees, 30-degrees, 45-degrees, 60-degrees, 75-degrees, and 90-degrees. The results show that the ply angle theta and the lami nate thickness had significant effects on the critical buckling load. The fiber volume fraction and the internal hydrostatic pressure had im portant effects on the critical buckling load. The cylinder length had a moderate influence on the buckling load. The thin shell with [theta /-theta]2 or [theta/-theta]s angle-ply laminate had better buckling-lo ad performance than the thin shell with [theta]4 off-axis laminate. Th e temperature profiles through the laminate thickness and various lami nates with the same thickness but with the different ply thickness had insignificant effects on the buckling behavior of the thin shells.