Vibration Characteristics of CFRP Laminated Composite Circular Cylindrical Shells Laminated in Different Structures

Abstract

The vibration characteristics of CFRP laminated composite shells were investigated experimentally and compared with those of isotropic shell. The laminates were composed of four-layered CFRP prepregs for angle-ply (unsymmetric laminate) and of five-layered ones for cross-ply (symmetric laminate). The isotropic shell with the same size as the composite shells was made of steel. In the experiment, these shells were mounted on a vibration table with clamped-free end condition, and excited horizontally by white noise. The natural frequencies and mode shapes were identified by modal analysis using STAR-system Software. The obtained frequencies of the shells were plotted as a function of circumferential wave numbers for each given axial wave number. It is found that the frequency curves of the laminated composite shell and the isotropic one cross at some circumferential wave number.