Design And Performance Analysis Of The Nanopins Based On Carbon Nanotubes

Over the past two decades,researches on the physical and chemical properties of carbon nanotubes(CNTs)are becoming mature thanks to the effort of various researchers,and CNTs have been widely applied as the typical nano material,while the design and the application of CNT-based nanodevices have been one of the hotspots in recent years.For now,great advances have been achieved in the nano mechanical devices,nano sensors,nano electric devices,nano energy-storage devices and nanofluid devices etc.based on CNTs.Apart from the nanodevices more reasonable,the further research should also focus on the connection and the integration of these nanodevices.Hence,utilizing the molecular dynamic simulation,this work has proposed the nanopins based on CNTs,and further investigated the service performance of the nanopins in order to facilitate the development of the integration of nanodevices and provide the theoretical reference for the design and research on the CNT-based connectors in future.This paper has firstly proposed a nanopin model based on a Y-type CNT,with the relatively appropriate gap confirmed,and investigated the effects of the positioning error,the system temperature and the moving velocity of the nanopin during the loading/unloading processes.The smaller gaps can contribute to the better fixity of the installed nanopin,but if the gap is too small,it would lead to the instability of the loading/unloading processes.Different from the macro pin,appropriate positioning errors can facilitate the installation of the nanopin to some extent.The increase in temperature can promote both the radial stability and the overall flexibility of the CNTs,giving birth to the oscillation,while the larger moving velocity can increase the impact between the nanopin and the silicon component,contributing to the instability of the loading/unloading processes.However,the temperature and the velocity in the normal range have no significant effect on the fixity of the proposed nanopin,and thus 300 K is taken as the typical value of the initial kinetic temperature,10 m/s is taken as the typical value of the moving velocity of the naopins.Then,in order to improve the computational efficiency and facilitate the further optimization,this paper has rebuilt the nanopins based on Y-type CNTs,and investigated the effects of the main structural parameters.For the Y-type CNTs,the length of the mounting end does not affect the fixity,while the long mounting end can make the loading/unloading processes unstable.The height of the branch plays a crucial role in the fixity of the nanopins.As the height of the branch increases,the unloading force of the nanopin increases firstly and then remains relatively stable with the evident oscillations.In general,the smaller included angle can enhance the fixity of the Y-type CNTs,but if the included angle is too small,it can also lead to the instability of the loading/unloading processes.Based on the comparison between the pushing approach and the pulling approach for the Y-type CNTs,this paper has further evaluated the installation performance and the shear performance of the nanopins with two branches.It is found that the loading force of the nanopin in pulling approach is an order of magnitude larger than that in pushing approach,and thus the pushing approach is more labor-saving and efficient.The joint of the branched CNTs can always make the trunk tube bended slightly,and thus the accurate screening and positioning error compensation are needed for the installation of the nanopins with two or more branches.The control end with a length of 200 ? and the position of the second branch are not responsible for the failed installation of the nanopins with two branches,but the branches too close to each other can attract and influence each other,resulting to the installation failure.Moreover,the radial stability of the CNTs plays an importance role in the shear process of the proposed nanopins.Finally,this paper has demonstrated five common nanopin models based on the structured CNTs,and conducted the loading/unloading tests to evaluate the applicability.The nanopin based on a Y-type CNT has the highest cost-performance ratio and there is room in the fixity to be enhanced further.The V-type CNT can not fasten the hole parts on its own,and thus it should be used cooperatively with another nanopin.Although the installation resistance and the unloading force are in the same order of magnitude,the installation in pushing approach is relatively easier than that in pulling approach for the 90° Y-type CNT.For the nanopin based on a T-type CNT,the attraction between the silicon hole and the nanopin can mislead the branch,leading to the installation failure.Furthermore,the cone-head straight CNT has the potential to be inserted into a smaller hole,and the termination of the straight CNT determines the axial fixity.