一方向ハイブリッド繊維強化材の動的引張破壊過程のシミュレーション

Abstract

The authors proposed a new failure process simulation model considering interfacial debonding between fibers and matrix as well as random fiber breaking based on a shear-lag theory, in which not only fiber elements but also matrix elements are included. The failure model was applied to characterize not only the static tensile failure process but also the statistical nature of hybrid effect of several types of unidirectional hybrid FRP in the previous reports.The present paper proposes a new dynamic failure process simulation model in which an additional time variable is also incorporated by taking the mass of fiber and matrix elements into account. An exact time-dependent stress redistribution process in a new composite failure model is evaluated by means of a finite difference scheme based on an increment method. The numerical results are shown and discussed for two types of unidirectional carbon (C)/glass (G) hybrid FRP models.As the results, it is shown that a time-dependent stress concentration factor is exactly evaluated by the simulation which is in good accordance with Hedgepeth's solution and that the stress in a carbon fiber is relieved to some extent due to the presence of glass fiber in hybrid C/G FRP. It is also shown that a clear difference exists between the static and dynamic tensile failure patterns for both types of hybrid FRP. It is furthermore shown that the dynamic stress-strain behavior and the acoustic emission are successfully simulated by taking the stress drop and the released strain energy due to fiber and matrix failures into consideration, which gives a more realistic behavior than the static simulation.