Influence of Side Stringer to Deck Deformation of Four-Lines High-Speed Railway Cable-Stayed Bridge with Double Cable Planes

Taking Beijiang Bridge as an example, using 3D finite element method, influence of side stringer to deck deformation of four-lines high-speed railway cable-stayed bridge with double cable planes is studied. The results show that the stiffness of the side stringer hardly influence the long wave of bridge deformation and the ratio of deflection to span, but significantly affects the short wave and transversal wave of the bridge deformation. The location of the side stringer influences the long wave slightly, but influences the short wave and transversal wave significantly. If the distance between the side stringer and the center of the main trusses changed, the long wave changes slightly, while the maximum short wave and transversal wave change a lot. The larger the distance, the less the transversal span of the deck and panel beams are, and the less the short wave and transversal wave are. The influence of the axial stiffness of horizontal K-shaped brace to the bridge deformation is small.

Research on the Hydrodynamic Forces of the Torsional Wave Propulsion by Extended Large-Amplitude Elongated-Body Theory

Torsional wave propulsion is different from transversal wave propulsion. Based on the characteristic feature of fin ray’s motion, we divide the dorsal fin along the radial direction into a series of long narrow bands. For each band, the analysis method is the same as the method computing hydrodynamic force of transversal wave propulsion. Then we give an integral calculation over fin ray’ length. We analyze the influence of the swing amplitude, frequency and length of fin as well as wave numbers and ratio of wave speed to swimming speed on hydrodynamic force. The calculated results show that: 1. the average thrust on the dorsal fin is directly proportional to the square of swing amplitude and frequency of fin ray. 2. The average thrust on the dorsal fin is directly proportional to the biquadrate of ray’s length. 3. As the wave numbers increase, the average thrust begins with a little increase and then turns to decrease. When the wave number roughly equals to 1.5, it reaches to a maximum. 4. If the fin frequency is fixed, the average thrust is of maximum when the ratio of wave speed to swimming speed roughly equals to 1.4.

Extensional and Transversal Wave Motion in Transversely Isotropic Thermoelastic Plates by Using Asymptotic Method

The present investigation is concerned with the study of extensional and transversal wave motions in an infinite homogenous transversely isotropic, thermoelastic plate by using asymptotic method in the context of coupled thermoelasticity, Lord and Shulman (1967, “The Generalized Dynamical Theory of Thermoelasticity,” J. Mech. Phys. Solids, 15, pp. 299–309), and Green and Lindsay (1972, “Thermoelasticity,” J. Elast., 2, pp. 1–7) theories of generalized thermoelasticity. The governing equations for extensional, transversal, and flexural motions have been derived from the system of three-dimensional dynamical equations of linear thermoelasticity. The asymptotic operator plate model for extensional motion in a homogeneous transversely isotropic thermoelastic plate leads to sixth degree polynomial secular equation that governs frequency and phase velocity of various possible modes of wave propagation at all wavelengths. It is shown that the purely transverse motion (SH mode), which is not affected by thermal variations, gets decoupled from rest of the motion. The Rayleigh–Lamb frequency equation for the plate is expanded in power series in order to obtain polynomial frequency equation and velocity dispersion relations. Their validation has been established with that of asymptotic method. The special cases of short and long wavelength waves are also discussed. The expressions for group velocity of extensional and transversal modes have been derived. Finally, the numerical solution is carried out for homogeneous transversely isotropic plate of single crystal of zinc material. The dispersion curves of phase velocity and attenuation coefficient are presented graphically.