A strip element method for analyzing wave scattering by a crack in an immersed composite laminate

A strip element method is presented for analyzing wave scattering by a crac k in a composite laminate submerged in a fluid. In this method, the fluid a nd laminated plate are modeled using two-nodal-line and three-nodal-line st rip elements, respectively. A system of governing equations of the fluid an d solid strip elements in frequency domain are derived using a variational method and the Hamilton principle, which are converted as a set of characte ristic equations in wave number domain by applying Fourier transform techni ques. A particular solution to the equations is obtained using a modal anal ysis method in conjunction with inverse Fourier transform techniques. A com plementary solution to the equations is found employing horizontal boundary conditions on cross sections at the crack tips. The addition of the partic ular and complementary solutions yields a general solution. Numerical examp les are presented for immersed steel and composite plates with either a hor izontal or a vertical crack. Computed results indicate that the fluid has c onsiderable influence on the wave fields scattered by a crack in a composit e laminate.