Investigation of the Effect of Low-Velocity Impact on Composite Plates with Preloading



In this study, the effects of low-velocity impact on the preloaded E-glass/ epoxy-laminated composites were investigated. Unidirectional reinforced E-glass/epoxy-laminated composite materials, [0/90]2s, were manufactured and tested. Dimensions of the specimens are 140 × 140 mm and its thickness is 2 mm. Impact tests were conducted in a vertical drop weight test device, which was specially manufactured. Impactor has geometry with a semi-spherical end of diameter 12 mm and weight 3.1 kg. In the tests, tension–tension, tension–compression (shear), and compression–compression preloads were applied on the specimen and low-velocity impacts were applied in the middle of the plate for the specimens under preload and the differences with regard to damage were specified. Force–time graphs obtained from the test specimens are given and discussed. Other graphs namely energy–time and force–displacement are calculated from the force–time graphs.