A Model of Damage Initiation in Singly Oriented Ply Fiber Metal Laminate under Concentrated Loads

Damage initiation is modeled in singlyoriented ply(SOP) Fiber Metal Laminate (FML) under concentrated loading conditions. The finite element method (FEM) is used based on the first order shear deformation theoryfor modeling damage initiation in SOP FML. The failure indices of the fiber prepreg and the metal laminate were calculated using the Tasi–Hill failure criterion and the Miser yield criterion respectively. To verify the model, failure analysis was conducted under uniaxial loading and cylindrical bending, then under concentrated loading. Results show that the model is good. An indentation test was then conducted to compare the damage initiation load with the calculated failure index. The test was conducted under two side clamped conditions in order to studythe fiber orientation effect. The indentation curve was fitted using the Hertz equation, and the damage initiation load was defined as the point of divergence of the fitted curve from the real indentation curve. The damage initiation loads were obtained for various fiber orientations and were compared with the calculated failure index. The experiment results closelymatched the calculated failure index. It follows that the present method accuratelycaptures damage initiation of SOP FML.