Experimental and numerical investigation of skin/lattice stiffener debonding growth in composite panels under bending loading

In the present paper, a comparative study on the debonding growth between skin and the lattice stiffeners is performed using both numerical and experimental procedures. To this end, two prevalent types of stiffener arrangement in designing of the lattice composite panels (orthogrid pattern) are considered. Furthermore, the detailed effects of the initial debonding pattern on the mechanical behavior of the structure are investigated. Then, finite element method (FEM) is chosen as the numerical approach and the interface debonding growth is simulated in the Abaqus software based on the bilinear CZM. In the experimental investigation, composite skin and stiffener ribs are manufactured using E-glass fibers and the prepared specimens are supposed to three-point bending loading and the debondig growth is detected experimentally. Generally the obtained results proved that the initial debonding pattern and stiffeners arrangement have a crucial effect on the bending behavior of the structure.