Numerical Simulation And Experimental Investigation On The Mechanical Behavior Of GLARE Laminates

Fiber metal laminates(FMLs) have promising applications in aviation industry. As novel light weight hybrid materials, they consist of bonded thin metal sheets and fibers embedded in resin. FMLs offer a unique combination of properties such as high specific static properties, excellent impact resistance and outstanding fatigue resistance.The performance evaluation of FMLs needs efforts due to their diverse structures, long curing cycles as well as complex failure modes. The thesis mainly focused on mechanical properties analysis of GLARE laminates by simulation and experiments. Firstly, a 3D progressive model of GLARE was built using ABAQUS by ductile damage for aluminum layers, Linde's model for prepregs and cohesive model for the interface. The interface parameters were obtained via lap-shear joints tension, float roll peeling, DCB and ENF tests, respectively. Predicted tensile and flexural behaviors of GLARE agreed well with experimental values. Secondly, Linde's model was modified by introducing a damage variable to prepregs in the thickness direction. The modified model was proved to be suitable for simulating the multi-interface delamination behavior of GLARE. Thirdly, the basic mechanical properties of thick GLARE based on 4/3, 5/4 and 6/5 structures were compared with GLARE 3/2. Results showed that the tensile properties were improved, while flexural and interlaminar strength decreased with the increase of plies. Finally, the fatigue initiation lives of GLARE 2-3/2 and GLARE 3A-3/2 were calculated according to Homan's theory using MSC.Fatigue. The predicted S-Ni curves exhibited good correspondence with experimental curves.The FEM model established in this thesis could well predict the mechanical properties and damage behaviors of GLARE laminates. It contributes to buliding the FMLs expert system, thus providing a basis for the materials selection of Chinese new generation aircrafts design.