An experimental and numerical study of FML cyclic bending behavior under cyclic three-point bending loading

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: An experimental and numerical study of FML cyclic bending behavior under cyclic three-point bending loading

ارائه دهنده: Provider: Alborz Mohebi

اساتید راهنما: Supervisors: Dr. Gholam Hossein Majzoobi

اساتید مشاور: Advisory Professors: Dr. Mohammad Kashfi

اساتید ممتحن یا داور: Examining professors or referees: Dr. Rahman Sefie, Dr. Amirhossein Mahmoudi

زمان و تاریخ ارائه: Time and date of presentation: 2023/3/11

مکان ارائه: Place of presentation: Seminar3

چکیده: Abstract: Fiber metal Laminate (FML) is a hybrid composite material that is widely employed in the aviation industry due to its excellent mechanical properties. FMLs are fabricated by sandwiching several layers of fiber-reinforced composite between two or more layers of metal. In this material, the ductility and durability of metal layers are combined with the fatigue and fracture properties of composite layers. In this work, the behavior of fabricated FML under the cyclic and monotonic 3-point bending test was experimentally and numerically investigated. The used FML was made of aluminum 2024 with 0.8mm thickness and E-glass fiber-reinforced epoxy (GFRE). This combination of layers produced an FML sample called GLARE. First, the mechanical properties of aluminum 2024 were determined by the tensile test. The mechanical properties of the GFRE layer were then calculated by a closed-loop optimization procedure using the iterative FEA method. In addition, a novel fixture was designed to apply cyclic 3-point bending loading by considering a simple support boundary condition for both displacement and load control circumstances. Moreover, a FE model was constructed in ABAQUS and validated under the 3-point bending loading and considering a cohesive layer between aluminum and GFRE layers to study the induced shear stresses un the bending loading. To determine the Chaboche cyclic material model, a MATLAB-based script was developed to analyze the cyclic behavior cycle by cycle to obtain the material constants. The FML samples were exponentially evaluated under the displacement control cyclic bending test with 2, 4, 6, 8, and 10mm deflections and load control cyclic bending test with 250 to 290N flexural force. The results showed that for ≤2mm deflection the materials revealed an elastic behavior. For the deflection range of 2 to 6mm, the behavior of FML was observed as cyclic plastic behavior. By increasing the maximum deflection to ≥6mm, the test samples were detached in a few cycles, and delamination or layers debonding clearly can be seen. The results of the load control test demonstrated that by increasing the flexural force no clear ratcheting behavior was observed