Kink-bands in rocks have been widely observed in nature and imitated in the laboratory, and the mechanism of their formation has attracted much attention from various researchers for many years. In this paper, a two-p...Kink-bands in rocks have been widely observed in nature and imitated in the laboratory, and the mechanism of their formation has attracted much attention from various researchers for many years. In this paper, a two-phase equilibrium model is presented in which the kink-bands are considered as a high-strain phase and the other regions outside kink-bands as a low-strain phase and the discontinuity of the deformation gradient and stresses is permitted across the interface between those two phases. Based on the present model, we conduct the analysis for the rocks under plane strain compression by finding the minimum value of the compressive loading at which the governing equations have real, physically acceptable solutions. It is revealed that for the rocks with strain-softening behaviour, two-phase equilibrium solutions exist, and the critical value of the compressive loading, the inclination angle of the kink-band, and the stresses and strains inside and outside kink-bands can all be determined by the solution, which are in good agreement with experimental measurements and observations.展开更多
The longitudinal compressive failure of a unidirectional carbon fiber reinforced plastic (CFRP) was studied using multiple-fiber model composites. Aligned carbon fibers were embedded in an epoxy matrix and put on a re...The longitudinal compressive failure of a unidirectional carbon fiber reinforced plastic (CFRP) was studied using multiple-fiber model composites. Aligned carbon fibers were embedded in an epoxy matrix and put on a rectangular beam. A compression test of the model composite was performed by means of a four point bending test of the rectangular beam. The number of carbon fibers was changed from one to several thousands, by which the effect on compressive failure modes was investigated. A compressive failure of a single-fiber model composite was fiber crush. The fiber crush strain was much higher than the compressive failure strain of the unidirectional carbon fiber reinforced plastic. By contrast, a compressive failure of a multiple-fiber model composite was kink-band. The longitudinal compressive failure mechanism shifted from fiber crush to kink-band due to an increasing number of fibers. Kink-band parameters i.e. kink-band angle and kink-band width were dependent on the number of closely-aligned carbon fibers.展开更多
基金supported by the National Basic Research Program of China (973 Program, No. 2007CB714001)
文摘Kink-bands in rocks have been widely observed in nature and imitated in the laboratory, and the mechanism of their formation has attracted much attention from various researchers for many years. In this paper, a two-phase equilibrium model is presented in which the kink-bands are considered as a high-strain phase and the other regions outside kink-bands as a low-strain phase and the discontinuity of the deformation gradient and stresses is permitted across the interface between those two phases. Based on the present model, we conduct the analysis for the rocks under plane strain compression by finding the minimum value of the compressive loading at which the governing equations have real, physically acceptable solutions. It is revealed that for the rocks with strain-softening behaviour, two-phase equilibrium solutions exist, and the critical value of the compressive loading, the inclination angle of the kink-band, and the stresses and strains inside and outside kink-bands can all be determined by the solution, which are in good agreement with experimental measurements and observations.
文摘The longitudinal compressive failure of a unidirectional carbon fiber reinforced plastic (CFRP) was studied using multiple-fiber model composites. Aligned carbon fibers were embedded in an epoxy matrix and put on a rectangular beam. A compression test of the model composite was performed by means of a four point bending test of the rectangular beam. The number of carbon fibers was changed from one to several thousands, by which the effect on compressive failure modes was investigated. A compressive failure of a single-fiber model composite was fiber crush. The fiber crush strain was much higher than the compressive failure strain of the unidirectional carbon fiber reinforced plastic. By contrast, a compressive failure of a multiple-fiber model composite was kink-band. The longitudinal compressive failure mechanism shifted from fiber crush to kink-band due to an increasing number of fibers. Kink-band parameters i.e. kink-band angle and kink-band width were dependent on the number of closely-aligned carbon fibers.
