The Impact Resistance And Finite Element Analysis Of Three-dimensional Orthogonal Woven Composites

On the base of parametric design theory and the finite element theory, a general single-cell model program of three-dimensional orthogonal woven composites is established in this paper with the CAD software Pro/Engineer by the analysis to the micro-fiber-reinforced of the three-dimensional orthogonal woven composite. The program can generate a corresponding model by setting the woven parameters, which can import into the finite element software ANSYS/LS-DYNA and simulate the quasi-static impact process. Comparing the results of the finite element analysis (FEA) with the measured ones, it shows that the two follow the same trend, and they have small error, which means that the FEA method is available for prediction of 3D orthogonal woven composites. What is more, in this paper, the trend of internal stress of the composite subject to impact load is discussed; some basic theories are provided for the three-dimensional woven composites'design and engineering applications. The main conclusions of this paper are as follows.(1) Universal testing machine was used in the quasi-static impact experiments, from which the load-displacement curves, energy absorption curves and failure modes were obtained. Through the analysis of the curves, it shows that the impact damage can be divided into several stages. It is in the beginning of the impact that the greater effect was found to the mechanical properties of composite materials. Besides the matrix was destroyed and fiber reinforcement was pulled-out, the composites'failure modes had the shear deformation during the impact. The composite took the compression failure on the front side and the tensile failure on the back side.(2) By computing the finite element model of the process of quasi-static impact with the explicit expression solver LS-DYNA, we got the results of the finite element model of the process of quasi-static impact. Compared with the load displacement curve, the material energy absorption curve and the failure mode we got from experiments, it showed that they had the same trend and the error was smaller, which mean that the FEA method is available for prediction of 3D orthogonal woven composites.(3) To analyze the destructive of the composite of the impact in micro-level, and it is clear and precise to see the concrete process of the destruction and the stress suffered at any time. Through the analysis of the fiber-reinforced body and the matrix with the stress changing over time, we can get that the stress of the composites increases following the impact, and the crisscross pattern area impacted by the punch got the utmost stress as well as the worst destruction, which is similar to laboratory experiments.(4) By analyzing the dynamic curves of the element at different levels of the cell, we can know that, the elements touching with the punch get failure because the elements'effective strain got the set value; the elements not touching with the punch get failure because they realize the biggest yield stress. The contact force between the punch and the fiber reinforcement is bigger than that between the punch and the matrix. The contract force between fiber reinforcement and matrix is small, it shows that they close contract with each other, and the boundary sliding is not distinct.