بررسي روش هاي ساخت و توليد كامپوزيت هاي حاوي صفحات با كي پيپر و مدل سازي مكانيكي آن ها

چكيده انگليسي :

A Study on Fabrication Methods of Composites Containing Buckypaper Sheets and Their Mechanical Modeling Mohammad Mahdi Zaeri mmz1230 m@yahoo com 17 April 2010 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree MSc Language Farsi Supervisor Dr Saeed Ziaei Rad szrad@cc iut ac ir Abstract Meeting the need for materials with new properties sought in modern technologies and due to ease in production composites have found wide applications in various industries specially aerospace and automobile industries With the advent of nanotechnology a new window was opened in different scientific fields including composites science and nanocomposites were introduced In these materials the superiority of material at nanometer scale over bulk state is exploited As an example with reduction of particle size down to nano scale the surface to volume ratio of material increases severely and as a result the interaction between matrix and reinforcement is promoted significantly Among nanocomposites those with polymer matrix reinforced by carbon nanotubes are of particular interest due to the remarkable properties of carbon nanotubes In a novel form of these nanocomposites which has recently attracted attention first a macroscopic thin and porous sheet composed of a random network of carbon nanotube bundles called buckypaper is made and then the composite is fabricated through infiltrating the resin into its pores High strength to weight ratio is one of the advantages of this nanocomposite In the present research firstly necessary preliminary studies and basics including nanotechnology properties of carbon element and its allotropes specially carbon nanotubes composite nanocomposite and modeling techniques were investigated Then methods of fabrication of buckypaper including suspension filtration frit compression domino pushing continuous production and hydroentangling and vacuum assisted resin transfer molding and dipping methods for producing composites containing buckypaper sheets were studied Then using an approach called molecular structural mechanics which is a combination of structural mechanics and molecular mechanics along with finite element method ANSYS package mechanical models were developed for graphene single walled carbon nanotubes multi walled carbon nanotubes nanotube bundles buckypaper and buckypaper epoxy nanocomposite In each step the geometry of the model was generated by MATLAB programming and then was transferred to ANSYS as an APDL input file and probable corrections were done on it Utilizing the models elastic behavior of the mentioned nanostructures was simulated under tensile shear or torsional loadings and applying equations of the theory of elasticity their Young s and shear moduli were obtained Effect of different parameters like graphene sheet length number of walls diameter and chirality of carbon nanotubes number of nanotubes in bundles porosity of buckypaper and alignment of bundles in buckypaper nanocomposite on elastic moduli was investigated The obtained results for carbon nanotubes are well close to the widely known values of about 1000 GPa for Young s modulus and 500 GPa for shear modulus Also comparison between the obtained results for buckypaper and its nanocomposite and values reported in other theoretical and experimental researches Young s modulus of buckypaper 0 2 12 2 GPa and Young s modulus of buckypaper nanocomposite 5 45 GPa shows good agreement and implies the efficiency of the applied modeling approach Results approve the idea of producing nanocomposite from buckypaper because the properties of nanocomposite show improvement over both buckypaper and epoxy in such a way that the improvement is six times the properties of the neat resin in some cases Key Words carbon nanotube buckypaper nanocomposite modeling mechanical properties molecular structural mechanics finite element method

زائري، محمد مهدي

بررسي روش هاي ساخت و توليد كامپوزيت هاي حاوي صفحات با كي پيپر و مدل سازي مكانيكي آن ها

نانو لوله كربني , خواص مكانيكي , مكانيك سازه اي مولكولي , روش اجزاء محدود