الفهرس 
FML Manufacturing Methods
EXPERIMENTAL PROCEDUREOnly 14 pages are availabe for public view
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Abstract
Fiber metal laminate (FML) is a composite material which contains various layers of metal and fiber reinforced composites (FRC). It is a hybrid composite as it contains two materials of matrices; resin adhesion, and metal. Also, it may contain different fiber materials.
FML displays the best properties of its constituent materials which provide light weight and good mechanical properties. The metal layers are preferred to be placed at the outer surfaces in order to withstand higher tensile and compressive stresses than that of FRC layers during loading. Fiber in FRC contributes in the mechanical properties through its length, shape, orientation, and material as it has high tensile strength. Resin matrix of the FRC is used in binding fibers together, transferring load to them, and shielding them from environment. It is also used in adhering FML layers together.
Most studies about FML are interested in unidirectional fibers oriented in various directions (0o, 90o, or 45o). The work objective is to study the FML which contains random chopped fiber glass due to the shortage in studying its characterization.
The introduced FML in this work is manufactured of E-random chopped fiber glass, epoxy resin, and aluminum alloy 5010-H18 using hand lay-up method and vacuum process. It is characterized in terms of Al sheets surface roughness (0.39, 1.07, and 1.63 µm), stacking of layers (2/1, 3/2, and 4/3 lay-ups), and Al sheets thicknesses (0.5, 0.7, and 1 mm) under applying different mechanical tests. These tests are the tensile test, the flexural test, the short beam test, and the in plane shear test. The density and the FML components’ volume fraction are also determined experimentally. The theoretical densities, young’s moduli, and ultimate tensile stresses are calculated and compared with the experimental results.
The experimental results show that the mechanical properties of the random chopped FML improve as the aluminum layers’ thickness and surface roughness increase, and as the FML layers’ stacking decreases.
The experimental density results of the random chopped FML are increased as the aluminum layers’ thicknesses are increased and as the FML layers’ stacking is decreased.
The experimental results of the FML components’ volume fraction show that as the thickness of the FML aluminum layers increases, the Al volume fraction
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increases while the volume fraction of fiber and resin decreases. But in case of the increase of the FML layers’ stacking, it is vice versa.
Consequently, the FML composite of stacking 2/1 lay-up and overall thickness 2.98 mm gives the best results of ultimate tensile stress (123.8 MPa), tensile young’s modulus (54.65 GPa), ultimate flexural stress (157.7 MPa), interlaminar shear stress (19.8 MPa), in-plane shear stress (66.55 MPa), and density (2377 kg/m3).
The calculated specimens’ thickness results show good agreement with the measured results by a percentage not exceeding 14%. The theoretical density results show good agreement with the experimental results by a percentage not exceeding 2%. The theoretical young’s modulus results show also good agreement with the experimental results by a percentage not exceeding 20%. The theoretical and the experimental results of the ultimate tensile strength show a wide scattering, and inconsistent agreement by a percentage ranging from (33% to 110%).
Generally, the microscopically observations of the failed specimens show integrity without entire separation, fiber pull out, and delamination as well Al and resin matrices cracking in case of tensile test, and resin matrix cracking in case of in-plane shear test.