Polymer composites is a typical material consisting of a matrix reinforced with fiber/filler and the general nature of construction of the material itself provides innumerable sites for the initiation of a defect or f...Polymer composites is a typical material consisting of a matrix reinforced with fiber/filler and the general nature of construction of the material itself provides innumerable sites for the initiation of a defect or for the growth of delamination. The life expectancy of composite structure requires a clear understanding of the material’s response to the growth of interlaminar delamination under Mode I, Mode II, Mode III and Mixed Modes. Fracture testing of fiber reinforced polymer-matrix composites is an active area of research. Even though substantial progress in the area of fracture testing has been achieved, there are still several problems awaiting solution. The new aspects in the experimental studies of interlaminar and intralaminar fracture toughness of polymer matrix composites were emphasized in this review paper. The different modes to evaluate the fracture energy were listed and their suitability was mentioned.展开更多
The mode mixity is defined based on nonoscillatory strain energy release rate components of delamination between two different orthotropic materials to evaluate the delamination behavior of laminated composites. The r...The mode mixity is defined based on nonoscillatory strain energy release rate components of delamination between two different orthotropic materials to evaluate the delamination behavior of laminated composites. The result showes that the relative location of the delamination through the thickness influences the mode mixity in a relatively well-regulated way, and that the reinforcement directions of the adjacent plies along the delamination front have a more complicated impact on the mode mixity. This is caused by the bending/twist coupling and bending/bending coupling in the stress field at the crack tip for delamination between multidirectional plies, which completely modifies the stress and strain fields ahead of the crack tip. These kinds of couplings account for the non- uniform distribution of mode mixity values along the delamination front. Application of appropriate mode mixity values is necessary for accurate prediction of delamination growth.展开更多
文摘Polymer composites is a typical material consisting of a matrix reinforced with fiber/filler and the general nature of construction of the material itself provides innumerable sites for the initiation of a defect or for the growth of delamination. The life expectancy of composite structure requires a clear understanding of the material’s response to the growth of interlaminar delamination under Mode I, Mode II, Mode III and Mixed Modes. Fracture testing of fiber reinforced polymer-matrix composites is an active area of research. Even though substantial progress in the area of fracture testing has been achieved, there are still several problems awaiting solution. The new aspects in the experimental studies of interlaminar and intralaminar fracture toughness of polymer matrix composites were emphasized in this review paper. The different modes to evaluate the fracture energy were listed and their suitability was mentioned.
基金The China Scholarship Council(No.[2007] 3020)the National Natural Science Foundation of China (No.50371069)the PhD Programs Foundation of Ministry of Education of China(No.20030699013)
文摘The mode mixity is defined based on nonoscillatory strain energy release rate components of delamination between two different orthotropic materials to evaluate the delamination behavior of laminated composites. The result showes that the relative location of the delamination through the thickness influences the mode mixity in a relatively well-regulated way, and that the reinforcement directions of the adjacent plies along the delamination front have a more complicated impact on the mode mixity. This is caused by the bending/twist coupling and bending/bending coupling in the stress field at the crack tip for delamination between multidirectional plies, which completely modifies the stress and strain fields ahead of the crack tip. These kinds of couplings account for the non- uniform distribution of mode mixity values along the delamination front. Application of appropriate mode mixity values is necessary for accurate prediction of delamination growth.
