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Su H.-D.,Lanzhou University of Technology | Su H.-D.,Lanzhou Petroleum Machinery Research Institute | Li S.-R.,Lanzhou University of Technology | Li S.-R.,Yangzhou University | Gao Y.,Lanzhou University of Technology
Jisuan Lixue Xuebao/Chinese Journal of Computational Mechanics | Year: 2010

Post-buckling of functionally graded material Timoshenko beams with surface-bonded piezoelectric layers subjected to temperature rise and electric field is studied. By accurately considering the axial extension and transverse shear deformation in the sense of theory of Timoshenko beam, geometrically nonlinear governing equations, for functionally graded beams subjected to thermo-electro-mechanical loadings were formulated. In the analysis, it was assumed that the material properties of the beam vary continuously as a power function of the thickness coordinate and that the piezoelectric layers are isotropic and homogenous. By using a shooting method, the obtained nonlinear boundary value problem was numerically solved and buckling and post-buckling response of the beams with the both ends fixed and subjected to transversely non-uniform heating and uniform electric field were presented. Characteristic curves of the post-buckling deformation of the beam varying with thermal load, the electrical load, and the power law index are plotted. Numerical results show that the tensional force produced in the piezoelectric layers by the voltage can efficiently increase the critical buckling temperature and defer the thermal post-buckling to occur. Due to being transversely non-uniform in the material properties, there exists tension-bending coupling effects in the beam even in uniform temperature rise in the thickness direction. However, for the piezoelectric-FGM beam with the two ends fixed the post-buckling is also bifurcation form under transversely non-uniform temperature rise. Source

Guo Z.-J.,Lanzhou Petroleum Machinery Research Institute | Zhou J.-J.,Lanzhou Petroleum Machinery Research Institute | Tao X.-J.,Lanzhou Petroleum Machinery Research Institute | Wang K.-D.,Lanzhou Petroleum Machinery Research Institute | Xie S.,Lanzhou Petroleum Machinery Research Institute
Corrosion and Protection | Year: 2010

The corrosion characteristics and applicability of 16MnR series materials used to make pressure vessel in oil field environment with high concentration of H 2S-CO 2-Cl - were studied by means of stress corrosion test and general corrosion test The results showed that 16MnR(HIC) and welded joint could resist the H 2S stress corrosion under the condition of pH < 6 and temperature <50 °C, and other 16MnR materials were sensitive to SSC (sulfide stress cracking) and HIC (hydrogen induced cracking). Immersion test should be carried out in the environment of simulating practical working condition for material selection. Source

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