Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanoc...Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.展开更多
A356 aluminum alloys reinforced with carbon nano-tubes (CNTs) were produced by stir casting and compocasting routes and their microstructural characteristics and hardness were examined.In order to alleviate the proble...A356 aluminum alloys reinforced with carbon nano-tubes (CNTs) were produced by stir casting and compocasting routes and their microstructural characteristics and hardness were examined.In order to alleviate the problems associated with poor wettability, agglomeration and gravity segregation of CNTs in the melt, CNTs were introduced into the melts by injection of CNT deposited aluminum particles instead of raw CNTs.Aluminum particles with mean diameters of less than 100 μm were first deposited by CNTs using Ni-P electroless plating technique and then injected into the melt agitated by a mechanical stirrer.The slurry was subsequently cast at temperatures corresponding to full liquid as well as 0.15 and 0.30 solid fractions.The results show that addition of CNTs to A356 matrix can significantly refine both full liquid and semi-solid cast microstructures.Hardness of the samples is also significantly increased by addition of CNTs and A356-CNT composite cast at 0.3 solid fraction produces the highest hardness.展开更多
文摘Carbon nanotube(CNT)/polymer nanocomposites have vast application in industry because of their light mass and high strength. In this work, a cylindrical tube which is made up of functionally graded(FG) PmP V/CNT nanocomposite, is optimally designed for the purpose of torque transmission. The main confining parameters of a rotating shaft in torque transmission process are mass of the shaft, critical speed of rotation and critical buckling torque. It is required to solve a multi-objective optimization problem(MOP) to consider these three targets simultaneously in the process of design. The three-objective optimization problem for this case is defined and solved using a hybrid method of FEM and modified non-dominated sorting genetic algorithm(NSGA-II), by coupling two softwares, MATLAB and ABAQUS. Optimization process provides a set of non-dominated optimal design vectors. Then, two methods, nearest to ideal point(NIP) and technique for ordering preferences by similarity to ideal solution(TOPSIS), are employed to choose trade-off optimum design vectors. Optimum parameters that are obtained from this work are compared with the results of previous studies for similar cylindrical tubes made from composite or a hybrid of aluminum and composite that more than 20% improvement is observed in all of the objective functions.
文摘A356 aluminum alloys reinforced with carbon nano-tubes (CNTs) were produced by stir casting and compocasting routes and their microstructural characteristics and hardness were examined.In order to alleviate the problems associated with poor wettability, agglomeration and gravity segregation of CNTs in the melt, CNTs were introduced into the melts by injection of CNT deposited aluminum particles instead of raw CNTs.Aluminum particles with mean diameters of less than 100 μm were first deposited by CNTs using Ni-P electroless plating technique and then injected into the melt agitated by a mechanical stirrer.The slurry was subsequently cast at temperatures corresponding to full liquid as well as 0.15 and 0.30 solid fractions.The results show that addition of CNTs to A356 matrix can significantly refine both full liquid and semi-solid cast microstructures.Hardness of the samples is also significantly increased by addition of CNTs and A356-CNT composite cast at 0.3 solid fraction produces the highest hardness.
