Numerical Simulation Of Mechanical Properties Of Nano-reinforced Magnesium Matrix Composites

The size of nanomaterials are very small,the actual tests are relatively difficult.So the finite element analysis software is used to study the mechanical properties of nanotubes reinforced composites,which can provide a theoretical basis for the research of nanotubes reinforced composites.The mechanical properties of nanotubes reinforced magnesium matrix composites were studied by large-scale simulation software Material Studio(MS)and ANSYS.The interface bonding strength and stability of doping phosphorus atoms on the nanotube adsorption Mg systems have been studied by CASTEP module of MS software using plane wave pseudopotential method with generalized gradient approximation based on density functional theory.It has been found that the bound energy of the system is reduced after doping phosphorus atoms,and the strength of the nanotubes is enhanced.While adsorption energy of the system is increased and the interface bonding strength between nanotubes and Mg is enhanced.The interface bonding strength between graphene and Mg is good.The three-dimensional stochastic distribution model has been established using the command flow of the secondary development program APDL of finite element software ANSYS.The numerical simulation of carbon nanotubes reinforced magnesium matrix composites which is subject to uniaxial tension and compression,and numerical simulation of carbon nanotubes and graphene reinforced magnesium matrix composites under the uniaxial tension has been carried out.It has been found that the first principal stress,von Mises stress distribution near the carbon nanotubes is extremely uneven in the process of the uniaxial compression and tensile simulation.The yield phenomenon and crack initiation is very prone to occur at the interface between carbon nanotubes and magnesium matrix.The mean value of first principal stress and von Mises stress at the interface between carbon nanotubes and magnesium matrix are the largest under the uniaxial tension when carbon nanotubes and magnesium matrix are 180?,so the crack initiation and yield phenomenon is very prone to occur.Under the uniaxial compression,the mean value of first principal stress is the largest when carbon nanotubes and magnesium matrix are 90? and easy to crack initiation.The mean value of von Mises stress is the largest when angle is 180?,so yield phenomenon is very prone to occur at this position.The von Mises stress distribution near carbon nanotubes and graphene is extremely uneven at the interface between reinforcements and magnesium matrix and between short-distance reinforcements,the yield phenomenon is extremely prone to occur.ANSYS finite element software has been also employed to set the parameters of the model and the fine mesh division.The unit life and death function has been used to realize the multi-load step with the APDL command flow.Then the numerical simulation of crack initiation and crack propagation during the process of uniaxial tensile failure of carbon nanotubes reinforced magnesium matrix composites has been conducted.It has been found that the cracks are first appeared at interface between carbon nanotubes and magnesium matrix,the prediction of crack propagation is consistent with the simulation results,the rate of crack propagation increases with the load increasing,especially after two parallel vertical cracks coincide.