Dynamic Response of Laminated Composites Subjected to Low-velocity Impact

Abstract

The dynamic response of E-glass/epoxy composite laminates under low velocity impact was experimentally investigated. Uni-directionally reinforced E-glass/epoxy laminates with the stacking sequence of [0°/-45°/45°/0°/ 90°/0°/45°/-45°/0°] s were studied with the aim of an impact test. The impact tests performed at impactor mass (30 kg) for three different impact velocities (2.0, 2.5, and 3.0 m/s) were conducted with a specially developed vertical drop weight testing machine. The radius of the impactor with a semispherical nose was 12 mm. Sample plate specimens that had dimensions of 180 × 50, 180 × 100, and 180 × 150 mm were clamped from two opposite sides while the other two sides were free. The center of each plate was exposed to impact loading. The differences in the impact responses of specimens with varying width are characterized. Moreover, it was shown that the peak force increased with the increase of the width of the specimen.

Experimental and numerical analysis of low velocity impact on a preloaded composite plate

“…Acceleration at t = t i was calculated based on Newton's second law of motion (a i = F i /m) [18]. F i value is the value obtained from the force sensor depending on time.…”

Impact resistance of gypsum board subjected to low velocity impact

“…Contact force-displacement changes are obtained as a result of kinetic analysis of low velocity impact (Uyaner and Kara [21]). …”

Effect of Low Velocity Impact Damage on Buckling Properties

“…The first integration gives the velocity and the second integration gives the displacement as a function of time. The equation of motion can easily be integrated imposing initial conditions (see [9]). Time axis has its origin at the contact time, while the reference quote h which is at a fixed, known distance from the upper undeformed surface of the specimen.…”

“…By integration of the force vs. displacement, the energies time history dur-ing the evolution of the test can be evaluated. The formulations of kinematic analysis are given in [9]. Pictures of damaged areas were retrieved from Adobe PhotoShop.…”

“…Low velocity impacts which may occur during manufacture, maintenance and by careless handling [2] are considered to be dangerous for a composite structure because the damage caused tends to be created on the back face or within the laminate and hence is difficult to detect [3,4]. The dynamic response of composite structures subjected to transient dynamic loading has been studied in terms of analytical, numerical [5,6] and experimental works [7][8][9][10]. Theoretically, many works have been developed with an aim of studying the behavior of composite targets under low-velocity impact.…”