Damage behavior of a bonded sandwich beam with corrugated core under 3-point bending

In this paper, the finite element method (FEM) is employed for analyzing the strength of a bonded sandwich beam with corrugated core. The adhesive layer (AL) is discretized and modeled with beam elements. A strength criterion and stiffness degeneration law of an AL is proposed. Effects of the configuration of the corrugated core on structural strength are investigated using a representative beam model containing three panels bonded with two corrugated layers. Two major geometrical parameters are considered: the angle between the oblique side and the horizontal bonding side of the corrugated layer and the overlap length of the two corrugated layers on both sides of the central panel. Numerical results obtained from 3-point bending tests show that the beam structure possesses maximum strength when the angle equals 90° and the overlap length of two corrugated layers is equal to the length of the horizontal bonding side of the corrugated layer. The crack expansion in ALs is also analyzed. It is found that the possibility crack expansion in the ALs near the upper and lower boundary is obviously greater than that in ALs near the neutral layer of beam structure. Furthermore, the flexibility of a bonded structure can be improved by enhancing the strength of the AL boundary.