The Finite Element Analysis Of Mechanics Properties Of The Carbon Nanotube Reinforced Magnesium Matrix Composite Material

The magnesium matrix composite has drawn word-wide attention in the field of metal matrix composite since the 1980's, because of its high strength-to-weight ratio, stiffness-to-weight ratio, excellent mechanical properties and physical properties, so it begins to appear in aviation, military, and car industries as a substitute material. The carbon nanotube (CNT) has excellent mechanical properties. The stiffness of CNT is 6 times that of steel, its stretch intension is 100 times that of steel, but the density of CNT is just 1/6 times that of steel. CNT can endure huge bend and twist deformation. So, it has very important practical significance, and huge economic benefit to research the mechanical properties of CNT/Mg composite material.In this paper, several key mechanical problems of CNT/Mg composite material were studied basing on the finite element model. The major contents were following:(1) The analysis model of CNT/Mg composite material which contained interface was built. The influential factors of composite material stress distribution were studied by changing a series of parameters, which included the strength of interface, the aspect ratio of reinforcement, the thickness of interface and the hemisphere shaped cap of CNT. It was found that the relatively stronger section of weak interface, the bigger aspect ratio, and the hemisphere shaped cap of CNT were beneficent for composite material mechanical properties. These results extended the previous report and provided an integrate understanding of CNT/Mg composite material mechanical properties.(2) The CNT/Mg composite material which contained crack was simplified to 2D model via axisymmetric relationship; the strength, range, and concentration of stress field near the crack tip were solved. It was found that the stress concentration occurs at crack tip, but range of affection was limited. The numerical value and variation ratio of stress intensity factor were increasing accompany with the crack length enlarging. These theories were benefit for improving the manufacture of composite material. (3) The composite material mesomechanics behaviors were discussed relying on the method of combining anisotropic material parameter and meson model. The anisotropic material parameter which was calculated by Material Studio software was proved by composite material stress-strain analysis. After that, this analysis method was applied to analyze the affection of aspect ratio to CNT/Mg composite material stress-strain distribution. These analyses were the bases to research composite material micro-mechanics behaviors.