Numerical and experimental analysis of dynamical behavior of composite T-joint with step wise graded adhesive zone based on functional behavior model

Due to stress concentration, adherends non-homogeneity (adherends materials, geometry and boundary conditions), and load transferring phenomenon, joints are the most critical locations in the structures especially composite structures. Enhance the strength of the adhesive joints and improve the dynamic behavior of the joints are the main goal of the most adhesive joints studies during the last decade. The effect of the step graded behavior of adhesive zone on dynamic behavior of composite T- joint is studied in present work. Finite element analysis (FEA) of carbon fiber reinforced polymer (CFRP) face-sheets, presented with ABAQUS 6.12-1 FEM code software. Loctite Hysol 3422, an epoxy adhesive, selected to bonding purpose and step wise behavior of adhesive region. Modal analysis and transient half-sine dynamic response of the composite T- joint are presented in this paper. Two verification processes employed to verify the dynamic modeling of manufactured sandwich panels and T-joint modeling. Step wise graded adhesive zone is a brilliant recommendation to control and improve the dynamic behavior of T-joints. The effect of the step wise graded adhesive zone on natural frequencies and mode shapes and transient response are compared for different topology of the step wise graded adhesive zone. It has been shown that the step wise graded adhesive zone cases changed the first natural frequency in range of 34 % and affected the mode shapes. Also the structural damping of the step wise graded adhesive zone cases and dynamic responses are smoother and more applicable.