The influence of a macrocrack on natural frequencies of a composite plate strip

Damages or imperfections have a well-known effect on rigidity and dynamic responses of a structure. Relevant researches state that these changes in dynamic responses can be used in practice to determine the size and the location of the damage. Effects of different geometrical and material parameters on natural frequencies of a composite plate strip with macro crack were studied in this thesis. Boundary value problems concerned were examined under two different boundary conditions. For the state of plane strain, mathematical modeling of the problems was implemented in the scope of the exact equations of the Theory of Elasticity. Due to the fact that discussed BVPs are incomputable with analytical approach, Finite Element Method was used for numerical solutions. So as to retrieve the solutions, a computer program was coded in MATLAB®. Numerical solutions were obtained for different boundary conditions, number of finite elements, composite material constants, size and location of the cracks. Acquired results for undamaged and cracked were compared. Keywords: Plate strip, crack, composite, finite elements, natural frequencies, matlab.