The Interfacial Mechanical Property Of CNT-alumina Ceramic Composites

The excellent property of electrics, mechanics and thermotics of CNT made itregarded as a new point of materials since it was found. In recent years, theexperimental study is tending toward perfection, and the numerical simulation is onfurther development. However, there are still some problems existed in the research ofnanocomposites. In the thesis, theoretical analysis and numerical simulation were usedto study the mechanical property of interface of alumina composites embedded bySWCNTs.In the first chapter, the development of research both in CNTs and compositesreinforced by CNTs are introduced. The property of mechanical and electrical ofCNTs-composites studied by experiment, simulate and theory are summarizedseparately in this part. The current relevant problems are also proposed. In the end, thewriter expounds the purpose of this topic and significance of research.In the second chapter, an appropriate mathematical model was established to studythe cohesive law of the interface of CNTs and alumina according to the theoreticalmethod based on Van deer Waals force. Thereforce, the relationships of normal stress oraverage shear stress and open displacement or relative slip were derived from the abovemodel. And it was also obtained that the interfacial stress transfer efficiency directlyaffected by the scale of interfacial stress.In the third chapter, the stress field of elastic mechanics and coordinatetransformation of the stress and strain of composites reinforced by short-staple wereintroduced firstly. the stress transfer efficiency of the interface of CNTs reinforcedalumina composites was derived. The stress distribution near the interface and theefficiency length of CNTs were also obtained. At last, the numerical simulation is usedto study the stress distribution of CNTs-alumina composites while the interface bondingis perfect. And the result was compared with those from theoretical arithmetic.In the fourth chapter, according to the above two sections, the interface slippingbehavior of CNTs-alumina composites was researched. A suitable simulation model wasestablished, in which, the tensile was loaded on matrix. Which made it possiable to meetthe need of interface slippage behavior, As the slipping behavior is began to occurred atthe occasion when the scale of interfacial shear stress needed is bigger than themaximum provided by Van deer Waals force. Then, solve the whole process. There were three procedures derived, firstly, the interface bonding was perfect, so the mechanicalproperty of nanocomposites was reinforced, at the beginning of slipping behavior, themechanical property of composites embedded by CNTs was still reinforced, at last, withthe march of slippage, the embedded CNTs decreased the mechanical property ofnanocomposites compared with pure alumina.