A New Method for Modeling of Initiation and Propagation of Delamination Between [0/θ°] Layers of Laminated Composites

In this article, initiation and propagation of delamination of a double cantilevered beam (DCB) is studied. The delamination of DCB specimen occurs between 0 degrees and theta (0) layers. Due to damage induced, during the loading, in the matrix of theta (0) layer, virtual crack closure technique (VCCT) as a well known method for simulation of initiation and propagation of the delamination for DCB is not able to model the propagation of delamination properly. To overcome this shortcoming, the stiffness of the damaged theta (0) layer is decreased with a developed technique in this study. The stiffness reduction technique (SR) is introduced in this paper to model the induced cracks in the matrix of the theta (0) layer. Then the stiffness reduction technique is coupled with the critical length parameter. The presented method is called stiffness reduction-critical length (SR-CL) method. By using SR-CL method, initiation and propagation of delamination for a [(0(2)degrees/90 degrees)(6)/0(2)degrees//theta degrees/(0(2)degrees/90 degrees)(6)/0(2)degrees] configuration in which theta = 0 degrees, 22.5 degrees, 45 degrees, 67.5 degrees, 90 degrees and for a cross ply laminate (0A degrees/90A degrees) (12) are modeled. The obtained results are in very good agreements with experimental data.