Low Velocity Impact Testing on Laminated Composites

Abstract

The response of composite laminates from transverse impact loading is known to vary with the speed of impact. In Low Velocity Impact (LVI) conditions, boundary effects usually dominate since the impact duration is longer between the laminate and the impactor. The global damage modes in LVI is also distinctly unique, whereby large deflections often occur, which depend highly on the shear properties (both in-plane and interlaminar) of the material. Therefore, characterisation of impact resistance and damage on LVI conditions are crucial before material selection for structural design. In this chapter, the LVI behaviour of composite laminates under LVI loading is investigated. The type of damage under LVI is also highlighted and discussed to obtain a detailed understanding of the impactor mass and velocity effects. The extent of delamination is studied using ultrasonic C-scan and radiograph images. Finally, where possible, fractographic studies have been undertaken to understand the influence of the interlaminar toughness on the impact resistance.