Investigation of dynamic properties of a polymer matrix composite with different angles of fiber orientations

Abstract

For the dynamic values of fiber-reinforced polymer matrix composite materials, elastic modulus and damping values are emphasized, and the two are desired to be high as much as possible, as the first is related to load bearing capacity, the latter provides the capability of energy absorption. In the composites, while fibers are usually utilized for reinforcement providing high elastic modulus and so high strength, matrix introduces a medium for high damping. Correct measurement of damping values is a critical step in designing composite materials. The aim of the current study is to measure the dynamic values of a glass fiber-reinforced polymer matrix composite, Hexply 913/33%/UD280, produced by Hexcel, using a vibrating beam technique. The specimens with different angles of fiber orientations (0, ±10°, ±20°, ±35, ±45°, ±55°, ±70, ±80 and 90) were manufactured from the composite prepreg and subjected to the clamped-free boundary conditions. Two different methods, the half power bandwidth and the logarithmic free decay, were used to measure the damping values to be able to compare the results. It has been revealed that the dynamic values are affected by the fiber orientations; for high flexural modulus the specimens with small angles of orientation, but for high damping those with large angles of orientation should be preferred. In general, the results are comparable, and the free decay method gave smaller values compared to the bandwidth method, with a little exception. It is suggested that the results (data) obtained from the test can be used for modal analysis reliably.