The Crack Tip Of Matrix In Carbon Nanotube Composites Intensity Factor Finite Element Analysis

A fast and effective numerical analysis method for the analysis of modern structural mechanics-- finite element simulation analysis(FEA) method. The widely used from elastic plasticity calculation, damage and fracture, dynamic mechanical, antipyretic conduction equation, electromagnetic field, electromagnetic coupling, fluid mechanics calculation. It uses the ordinary differential equation solver as the support software, uses the basic principle of the finite element and the thought derivation basic theory formula, and thus carries on the thorough research. Crack is an important research object of the fracture mechanics of materials, linear elastic fracture mechanics crack tip should stress intensity factor value is crack tip stress field intensity theory of judgment, and stress intensity factor is a measure of the crack tip stress field intensity of key parameters.The first chapter of this paper briefly introduces the research background, research status and application prospects of CNTs/AZ91 D composites at home and abroad. On the basis of this study, the finite element model of CNTs/AZ91 D composites with different length and diameter of the matrix was established by using the finite element software. The matrix crack length, nano carbon length diameter ratio, reinforcement elastic modulus, elastic modulus of the matrix of magnesium matrix crack tip should be the influence of stress intensity factor.The strengthening mechanism and fracture mode of CNTs/AZ91 D composites were discussed.The simulation results show that the magnesium matrix of three-dimensional crack tip should stress intensity factors along with the growth of the crack length shows a trend of becoming bigger and bigger, and when the crack throughout the matrix expansion to enhance the contact surface of the body and the matrix should be a sharp drop in stress intensity factor, the crack change trend with the bilateral materials similar. Stress singularity at the crack tip stress field.The stress intensity factor of the crack tip decreases with the increase of the elastic modulus of the reinforcement, and increases with the increase of the elastic modulus of the matrix.After the third chapter further establish the three-dimensional finite element model of Ni-CNTs/AZ91 D composite, reinforcement length to diameter ratio on the crack tip should stress intensity factor of influence Ni-CNTs/AZ91 D composite interface layer thickness of the interfacial layer, elastic modulus, are studied. Research results show that the crack tip in Ni-CNTs/AZ91 D composite matrix should stress intensity factor than CNTs/AZ91 D composite matrix crack tip should stress intensity factor becomes larger, and when the crack extended to the reinforced body and the matrix near the contact surface. Ni-CNTs/AZ91 D composite crack tip should stress intensity factor than near the crack tip of CNTs/AZ91 D composite should stress intensity factor decreased intensity. And the stress intensity factor of the crack tip increases with the increase of the thickness of the interface layer, and the stress intensity factor of the crack tip decreases with the increase of the elastic modulus. When the crack length is smaller, the length to diameter ratio(A < 30) has little effect on the stress intensity factor of the crack tip. When the crack length is larger and the length to diameter ratio(A > 30) is larger, the stress at the crack tip decreases with the increase of the crack length.In the fourth chapter, the CNTs/AZ91 D composites are summarized and prospected.