Interface Failure Mechanism And Strengthening Technology Of Fiber-Reinforced Metal Matrix Composites

How to accurately predict and control the peeling and fracture behavior of fiber-reinforced metal matrix composites and clarify its peeling and fracture failure mechanism is a key scientific issue for fiber-reinforced metal matrix composites.Aiming at scientific problems,the interface peeling crack propagation fracture failure process simulation technology of fiber-reinforced metal matrix composite materials composite has been constructed,by which the effect of fiber bridging on the composite interface peeling crack propagation fracture failure process was researched,and the strengthening mechanism of interfacial fiber bridging was explained.The synergetic relevance theory among the bridging fiber characteristics-interface fracture toughness-interface peeling crack propagation fracture failure critical load has been constructed;Based on the synergetic correlation curve,the failure design criteria for preventing the rapid instability and propagation of fiber bridge reinforced composite interface crack are proposed.Finally,based on the characteristics of over-molding and shear thinning constitutive relationship of polymer melt,a full three-dimensional non isothermal theoretical model and simulation technology of over-molding process are constructed.The relationships among the molding process parameters,fiber distribution and orientation,the evolution of composite interface temperature field were established,and the key control parameters were clarifiedThe critical load of the failure is controlled by the fiber density,the orientation angle of the fiber,initial precracking area,damage initiation stress and critical strain energy release rate,which is positively correlated with the effective bridging fiber density,damage initiation stress and critical strain energy release rate,however,has a negative correlation with the initial precracking area.The critical load of the composite interface debonding crack can be increased by increasing the effective bridging fiber density,damage initiation stress and critical strain energy release rate,or decreasing the initial precracking area.The collaborative coupling correlation curve of bridge fiber characteristics—interface fracture toughness—interface crack propagation failure critical load under the condition of equal critical load P_CR is studied and constructed.Based on the collaborative combined operating point of the composite interface effective bridging fiber density,damage initiation stress,critical strain energy release rate and initial precracking morphology,Innovative ideas for establishing design criteria to prevent debonding crack propagation and fracture failure induced by fiber bridging strengthening interface was proposed.Through the optimization of molding process parameters and bridging fiber characteristic parameters,the effective bridging fiber density of the composite interface can be as high as 61.5 fibers/mm²,by which the best strengthening effect of fiber bridging composite interface can be obtained...