Surface Roughness and Fiber Angular Orientation Analysis Toward Laminated Composite Crack Propagation

Composite is a material that consisting of two or more materials, either micro or macro, where the properties of the material differ in shape and chemical composition from the original substance. In this study, fatigue testing of fiber metal composites was carried out to determine the rate of crack propagation so that the age of the fiber metal composite specimen was known. The independent variable in this research is the angular orientation of the carbon fiber and the surface roughness of the aluminum with the dependent variable response is the bridge crack rate. The manufacture of fiber metal laminates specimens uses the Vacuum Resin Infuse (VARI) method, which uses a vacuum pump as a means to flow the resin from the reservoir to the mold. This method is used to minimize the occurrence of air bubbles trapped on the specimen which causes porosity defects which will reduce the strength of the metal laminates specimen itself. Fatigue testing is performed using the stress amplitude method. That is, the value of the load when the tensile test is one third of the tensile strength. After the fatigue test was carried out, the results were obtained on specimens with an angular orientation of 0/90 ° fibers, the crack propagation rate slowed down with a cycle value of 90000 in specimens with a surface roughness value of 2.128 µm then decreased cycles on specimens with a value of 2.887 µm, namely 11000 cycles.