Numerical Analysis on Low-Velocity Impact Damage of Laminated Composites by Combining Continuum Damage Mechanics with Cohesive Zone Model

摘要

When laminated composites are applied in the aircraft, they may suffer from tool dropping, stone hitting, bird impact and so on. These impactors can be summarized as drop-weight (high mass, low velocity) or gas-gun (low mass, high velocity) [1]. It is known that the plate-shell structure of fiber reinforced composites is sensitive to transverse impact, even slight lateral impact may lead to intraply and interlaminar damage. Thus, the ability of laminated composites to resist impact has been the focus of attention. Focusing on the low-velocity impact damage, the mainstream explanations for its damage mechanism have the following two ways. Choi and Chang [2] put forward that the top delaminations were mainly induced by inner shear cracking whereas the bottom delaminations were mainly induced by surface bending cracking. Renault [3] proposed to give matrix cracking a precursor role regarding the development of specific delamination. This idea has been globally admitted in literatures [4-6]. Currently, there has been much work on carrying out the relevant researches on drop-weight by experimental and simulated methods [7-10]. These studies include the response of laminated composites to low-velocity impact as well as the initiation, propagation and extent of damage in the structure. Also, the influences of such factors as thickness, curvature, stacking sequence and boundary conditions on the structural behavior under low-velocity impact are discussed. Considering that the experimental methods are time and labor consuming and costly, more and more scholars start to use numerical simulation technology for correlative research work.