Title page for etd-0807115-204820


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URN etd-0807115-204820
Author Heng-jui Ou
Author's Email Address No Public.
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Department Mechanical and Electro-Mechanical Engineering
Year 2014
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Numerical Studies on Heat Transfer and Plastic Flow of Dissimilar Materials in Friction Stir Welding
Date of Defense 2015-07-29
Page Count 97
Keyword
  • material flow
  • pin tool
  • dissimilar materials
  • friction stir lap welding
  • Abstract In this study, a theoretical model suitable for the friction stir lap welding (FSLW) process is established under the steady-state conditon. The momentum conservation, energy conservation and continuity equations are simultaneously solved to investigate the temperature distribution and material plastic flow of the workpiece. Effects of temperature and strain rate on the effective flow stress are considered. First, the results obtained from this model are compared with those measured from FSLW of alloy 6061 on Ti–6Al–4V in the literature to correct the input parameters. Then, effects of FSLW operating parameters on the temperature distribution, material plastic flow behavior of the workpiece are investigated.
    Simulated results show that the contact frictional heating between the tool and workpiece is the main heat source. The material flow speed of the workpiece is significantly influenced by its temperature, and the thermal conductivity of the workpiece has an important effect on its temperature. Finally, for the dissimilar material of FSLW welding mechanism is investigated, and the empirical equation suitable of the steady-state maximum interface temperature rise for the pin contact with lower workpiece is derived as:
    ∆T_2=(1+k_Tool/k_1 )^(-1) μ_f 〖〖pωR〗_S〗^3 L_2 (L_1/k_1 +L_2/k_2 +1/h_1 )/(L_1/k_1 +L_2/k_2 ) (108.36/(k_1 〖k_2〗^0.672 )-0.0033)×(-U+20.8)
    For the FSLW of alloy 6061 (6 mm) on Ti alloy (2.5 mm), the interface temperature between these two sheets can be achieved to about 520~550°C using the tool downward pressure 94 MPa, rotation speed 1400 rpm, and feed rate 20 mm/min.
    Advisory Committee
  • Yeau-Ren Jeng - chair
  • Jen-Fin Lin - co-chair
  • Rong-Tsong Lee - advisor
  • Yuang-Cherng Chiou - advisor
  • Files
  • etd-0807115-204820.pdf
  • Indicate in-campus at 5 year and off-campus access at 5 year.
    Date of Submission 2015-09-07

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