Nonlinear Vibration Caused by Beam of Cable Structures
The nonlinear vibrations of cables excited by thevibration of beam were investigated. At first, a simpleconnection condition and boundary condition of thecable-stayed beam structure were applied. Thenonlinear equations of motion of the cable-stayedbeam structure were derived, and the static sag of thecable as well as the geometric nonlinearity wasconsidered, moreover, Appling the multi-scaleperturbation method, the nonlinear vibrations ofcables were studied, the nonlinear vibration responseof cables was analyzed by the Runge-Kutta numericalmethod to obtain the frequency-response curves. Theresults indicate that the beam small scale vibration canstimulate the cable the large scale movement whenlocal oscillation frequency of beams is in the certainregion, it affects the cable-stayed beam structure thestability and the security in the Engineering. For thesystem in which the damping and the frequency ratiowas given, the enough low excitation amplitudes canavoid the system resonances.
On the symmetric modal interaction of the suspended cable: Three-to-one internal resonance
Abstract The two-mode nonlinear response of a suspended cable subjected to the primary resonance is investigated, and the three-to-one internal resonance is analyzed. Because the treatment of Galerkin discrete models of spatially continuous systems with initial curvature may lead to erroneous quantitative or even qualitative results, the method of multiple scales is applied to directly attack the nonlinear partial differential equation and the boundary conditions, which leads to the modulation equations for the primary resonance of either the first or third symmetric mode. The Newton–Raphson method and the pseudo-arclength scheme are used to obtain the frequency-response curves and force-response curves, and the dynamic solutions of the modulation equations are also investigated.
Effects of reservoir volume on performance of pulse tube cooler.
A pulse tube cooler has the advantages of long-life and low-vibration over conventional cryocoolers such as G-M and Stirling coolers because of the absence of moving parts at low temperature. On the other hand, the combination of a reservoir and orifice is indispensable to optimize the performance of pulse tube coolers. In order to make the pulse tube cooler compact for practical applications, the volume of reservoir should be minimized. This paper analyzes the effects of the reservoir volume on the thermodynamic performance of various components in a simple orifice and a double-inlet pulse tube cooler by combining a linearized model with a thermodynamic analysis. Expressions of entropy production for those components are presented. The results show that the reservoir volume has a significant influence on the entropy production in the various components when the reservoir to pulse tube volume ratio is smaller than about 5. The ratio is important to determine the minimum reservoir volume for a pulse tube cooler. Optimum settings for a double-inlet pulse tube cooler are also discussed.