NATURAL VIBRATION OF FREE, LAMINATED COMPOSITE TRIANGULAR AND TRAPEZOIDAL SHALLOW SHELLS

Natural vibration of completely free, laminated shallow shells having triangular and trapezoidal planforms is studied. Algebraic polynomials are used in a Ritz analysis to determine the natural frequencies. Det ailed convergence studies are made and showed that relatively accurate results can be obtained. The lowest six frequencies for various shell configuration and material lamination angle are listed. Both right an d symmetrical triangular and trapezoidal shell configurations are cons idered. The methods can be used for generally shaped planforms, genera l lamination angle and stacking sequence and general material properti es.