Title page for etd-0808115-141756


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URN etd-0808115-141756
Author Chen-wen Huang
Author's Email Address adamhang852@gmail.com
Statistics This thesis had been viewed 5338 times. Download 608 times.
Department Mechanical and Electro-Mechanical Engineering
Year 2014
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Examination on the mechanical properties of tungsten nanowires by molecular statics simulation
Date of Defense 2015-07-20
Page Count 85
Keyword
  • intrinsic strength
  • loop test
  • Tungsten
  • tension test
  • molecular statics
  • Abstract The new improved loop test had been examined to predict the limited strength of nanowires. We employ molecular statics (MS) simulations to obtain the mechanical properties of nanowire based on the improved loop test method, and compared with the traditional tensile test method in this study. First, we compared Finnis-Sinclair EAM potential, alloy EAM potential and 2nn-MEAM potential for simulating tension tests of bulk tungsten (W) and compared with experimental data. The simulation results indicated the 2nn-MEAM potential is the best force field for describing the mechanical behavior of bulk tungsten. Furthermore, the size-effects of W nanowires were investigated in order to avoid the influences of model dimension. The tungsten nanowire with diameter of 12 nm was chosen because it avoided the obvious size-effect and the model was suitable to simulate by using MS.
    The loop test and the traditional tensile test are simulated to obtain the maximum strain of W nanowires. In order to construct the nature structure with defects, we create random vacancies in the tungsten nanowires by deleting random atoms. Moreover, we compared the results from perfect and defective structures with the two methods by tension and bending simulations. The results present the random vacancies cannot influence the new loop test significantly, instead of traditional tensile test. Therefore, the new loop test becomes the mainstreaming means for predicting the limited strengths of defective and perfect structures in the nanoscale mechanical analyses.
    Advisory Committee
  • Cheng-Tang Pan - chair
  • Che-Hsin Lin - co-chair
  • Chih-Chao Yang - co-chair
  • Shin-Pon Ju - advisor
  • Files
  • etd-0808115-141756.pdf
  • indicate access worldwide
    Date of Submission 2015-09-08

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