This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser（SCR） by using the finite element method. The critical top tension is the minimum top tension that c...This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser（SCR） by using the finite element method. The critical top tension is the minimum top tension that can maintain the equilibrium of the SCR. If the top tension is smaller than the critical value, the equilibrium of the SCR does not exist. If the top tension is larger than the critical value, there are two possible equilibrium configurations. These two configurations exhibit the nonlinear large displacement. The configuration with the smaller displacement is stable, while the one with larger displacement is unstable. The numerical results show that the increases in the riser＇s vertical distances, horizontal offsets, riser＇s weights, internal flow velocities, and current velocities increase the critical top tensions of the SCR. In addition, the parametric studies are also performed in order to investigate the limit states for the analysis and design of the SCR.展开更多
For statically indeterminate structure, the internal force will be changed with the translation of the supports, because the internal force is related to the absolute value of the stiffness EI. When the tension is dif...For statically indeterminate structure, the internal force will be changed with the translation of the supports, because the internal force is related to the absolute value of the stiffness EI. When the tension is different with the compression modulus, EI is the function of internal force and is not constant any more that is different from classic mechanics. In the other words, it is a nonlinear problem to calculate the internal force. The expression for neutral axis of the statically indeterminate structure was derived in the paper. The iterative program for nonlinear internal force was compiled. One case study was presented to illustrate the difference between the results using the different modulus theory and the single modulus theory as in classical mechanics. Finally, some reasonable suggestions were made for the different modulus structures.展开更多
On the basis of the Young-Laplace Equation that describes the pressure difference between each side of a curved liquid surface, a static equilibrium model is established to describe the surface shape of the weld bead....On the basis of the Young-Laplace Equation that describes the pressure difference between each side of a curved liquid surface, a static equilibrium model is established to describe the surface shape of the weld bead. The geometrical model for the molten pool is included, which is essential to explain the undercut phenomenon during high speed bead-on-plate welding. The results got from an iteration algorithm show that it is the force balance on the liquid mixture of the deposited metal and the molten base metal that causes the undercut. Some factors and their effects are also analyzed.展开更多
磁通量索力传感器(Elasto-Magnetic force sensor,EM sensor)作为一种非接触式测量的传感器,与其他索力传感器相比,具有长期稳定性与可靠性好、耐久性高、使用寿命长的突出优势,在预应力拉索的索力监测上应用广泛。本文对磁通量索力传...磁通量索力传感器(Elasto-Magnetic force sensor,EM sensor)作为一种非接触式测量的传感器,与其他索力传感器相比,具有长期稳定性与可靠性好、耐久性高、使用寿命长的突出优势,在预应力拉索的索力监测上应用广泛。本文对磁通量索力传感器的工作原理、发展脉络及研究热点进行阐述,对该技术工程应用的状况与面临的难题进行总结,并对传感器的技术发展趋势进行讨论与展望,以期为相关领域的研究人员在磁通量索力传感器应用及技术上的研究提供参考。展开更多
基金supported by the Thailand Research Fund(TRF)through the Royal Golden Jubilee Ph.D.Program(Grant No.PHD/0112/2553)the National Research University(NRU)initiative
文摘This paper aims to present the critical top tension for static equilibrium configurations of a steel catenary riser（SCR） by using the finite element method. The critical top tension is the minimum top tension that can maintain the equilibrium of the SCR. If the top tension is smaller than the critical value, the equilibrium of the SCR does not exist. If the top tension is larger than the critical value, there are two possible equilibrium configurations. These two configurations exhibit the nonlinear large displacement. The configuration with the smaller displacement is stable, while the one with larger displacement is unstable. The numerical results show that the increases in the riser＇s vertical distances, horizontal offsets, riser＇s weights, internal flow velocities, and current velocities increase the critical top tensions of the SCR. In addition, the parametric studies are also performed in order to investigate the limit states for the analysis and design of the SCR.
文摘For statically indeterminate structure, the internal force will be changed with the translation of the supports, because the internal force is related to the absolute value of the stiffness EI. When the tension is different with the compression modulus, EI is the function of internal force and is not constant any more that is different from classic mechanics. In the other words, it is a nonlinear problem to calculate the internal force. The expression for neutral axis of the statically indeterminate structure was derived in the paper. The iterative program for nonlinear internal force was compiled. One case study was presented to illustrate the difference between the results using the different modulus theory and the single modulus theory as in classical mechanics. Finally, some reasonable suggestions were made for the different modulus structures.
文摘On the basis of the Young-Laplace Equation that describes the pressure difference between each side of a curved liquid surface, a static equilibrium model is established to describe the surface shape of the weld bead. The geometrical model for the molten pool is included, which is essential to explain the undercut phenomenon during high speed bead-on-plate welding. The results got from an iteration algorithm show that it is the force balance on the liquid mixture of the deposited metal and the molten base metal that causes the undercut. Some factors and their effects are also analyzed.
文摘磁通量索力传感器(Elasto-Magnetic force sensor,EM sensor)作为一种非接触式测量的传感器,与其他索力传感器相比,具有长期稳定性与可靠性好、耐久性高、使用寿命长的突出优势,在预应力拉索的索力监测上应用广泛。本文对磁通量索力传感器的工作原理、发展脉络及研究热点进行阐述,对该技术工程应用的状况与面临的难题进行总结,并对传感器的技术发展趋势进行讨论与展望,以期为相关领域的研究人员在磁通量索力传感器应用及技术上的研究提供参考。
