Study Of Mechanical Properties For Fiber/Matrix Interface

The interface is one of the key components of fiber reinforced composite materials, which plays an important role in mechanical properties and the damage process of composite. As an important means for evaluating the surface modification of reinforcing fibers and the quality of composite interface, single fiber pull-out test has been highly regarded in recent years. Based on the results of micro-experiments, single fiber pull-out tests for glass fiber/concrete composite were numerically simulated in this thesis.Considering different embedded fiber length, the numerical simulations were carrying out by using the finite element software ANSYS and the method of element birth and death.Compared with the experimental data, the numerical simulations were proved to be reasonable.The effect of the grafted fiber on single fiber pull-out test of glass fiber/concrete composite was discussed. The results show that the epoxy resin grafted fiber has a great effect on the interfacial shear strength and damage mode. The interfacial damage process and the load-displacement relationship at the end of single fiber were obtained. The effect of thickness and roughness of the interface (layer) on the interfacial shear strength and damage mode was also discussed. The results show that the rough grafted interface has higher bond strength because of the existence of mechanical bite force.The effect of interfacial elastic modulus on the damage mechanism and macro-mechanics feature of glass fiber/concrete composite was studied. Single fiber pull-out tests for the fiber reinforced brittle matrix composite with different interfaces were numerically simulated. From the simulation, one can be concluded, that the soft interface is good for higher toughness of the composite, while the stiff interface is not very useful to improve the toughness. Moreover, single fiber pull-out tests for different fiber/matrix composite systems were numerically simulated and discussed. The results are useful to study the damage mechanism and mechanical properties for this kind of composite.