by Guimard, Jean-Mathieu; Allix, Olivier; Pechnik, Nicolas; Thévenet, Pascal

This paper addresses the question of rate effects in the propagation of delamination cracks in Composite Fiber-Reinforced Plastics (CFRPs). In order to make use of a simple loading device, a mode-II case is used as the basis of the experimental study. The position of the crack is recorded quantitatively by means of a high-speed camera and dedicated image processing techniques. The delamination process is modeled by means of an interfacial Continuum Damage Model (CDM), similar to Cohesive Zone Model (CZM) approaches. In order to make suitable comparison between test and explicit finite element simulation of the test, criterai of proper temporal and spatial discretization have been derived. They ensure a fine description of the process zone and a proper description of the degradation evolution of the interface. Using such simulations and direct comparisons with the tests results, it is shown that the experimental results cannot be reproduced numerically without introducing rate effects. Then, it is proposed and identified by means of comparison between experiments and numerical simulation a bounded-damage-rate interfacial model. The main consequence of the proposed rate-dependent model is that it introduces a maximum crack velocity which is a function of the maximum damage rate. The dependence of the critical energy release rate on the crack’s velocity is analyzed, which leads to the identification of an equivalent rate-dependent fracture mechanics criterion.

DOI: 10.1007/s10704-009-9410-z
Online Date: 10/9/2009
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