A dynamic stiffness element for flexural vibration analysis of delaminated multilayer beams is developed and subsequently used to\r\ninvestigate the natural frequencies and modes of two-layer beam configurations. Using the Euler-Bernoulli bending beam theory,\r\nthe governing differential equations are exploited and representative, frequency-dependent, field variables are chosen based on the\r\nclosed form solution to these equations. The boundary conditions are then imposed to formulate the dynamic stiffness matrix\r\n(DSM), which relates harmonically varying loads to harmonically varying displacements at the beam ends. The bending vibration\r\nof an illustrative example problem, characterized by delamination zone of variable length, is investigated. Two computer codes,\r\nbased on the conventional Finite ElementMethod (FEM) and the analytical solutions reported in the literature, are also developed\r\nand used for comparison. The intact and defective beam natural frequencies and modes obtained from the proposed DSM method\r\nare presented along with the FEM and analytical results and those available in the literature.
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