Applied Mechanics and Materials Vols. 268-270

Abstract: The design load plays an important role in research on structural analysis of surface warship. The methods for the design loads have been proposed by many famous classification societies rules. In this paper the methods of the design loads from the native existing classification societies rules and foreign rules were studied, and based on these rules, the design loads of a warship were obtained. Meanwhile, segment model self propulsion tests of this ship were performed in heading waves in the seakeeping tank to confirm the design values. Comparisons of calculation of classification societies rules with experimental data were also conducted and results were summarized in this paper. It is concluded that the evaluation methods from the rules don’t take full account of the importance of slamming，the slamming moments from rules are fewer and wave moments are too large while those from BV rules give relatively conservative design values for the surface warship.

Abstract: The efficacy of single anti-galloping equipments is limited due to shortage of relevant galloping mechanisms or more complex wind and ice conditions. In this paper, a combination anti-galloping method between interphase spacers and rotary clamp spacers is proposed to avoid or reduce the “whole galloping” and “subspan” galloping phenomenon which occur notwithstanding installing interphase spacers. The combination method is designed using multi-mechanisms anti-galloping design, controlling phase-to phase clearance, affecting structural whole properties, and changing iced shape. The galloping critical conditions of wind and ice to excite “whole galloping” and “subspan” galloping are increased by using rotary clamp spacers than by using only interphase spacers. The anti-galloping effect can be improved greatly by using the combination method.

Abstract: Determining how to quickly and economically remove the ice on the airport runways, city roads and bridges is becoming a tough problem to keep the traffic flow and safe in the snow and icy weather. In this context, this paper presents a new method that combines thermal deicing method, water-jet cutting technology with mechanical deicing method, based on analyzing the deficiencies of the existing ice removal methods. Then, it introduces the construction of thermal water-jet and mechanical deicing equipment, mainly the design of thermal water-jet device, and presents the experimental results by repeated indoor experiments. The results indicate that the device can perform well in deicing work, and satisfy to the design requirements.

Abstract: With 3MW composite blade wind turbine blade as an example, according to the momentum blade element theory, optimized the design of aerodynamic shape, established the Three-dimensional model of blade through coordinate conversion, and made the stress check of structure and modal analysis using the finite element method, and more detailed description of the design methods and techniques of large composite wind turbine blades

Abstract: On the basis of the lumped electric charge, the inner P type body region and the N-type drift region electric charge of VDMOSFET were respectively shown in three districts: accumulation, depletion, inversion. The application of carrier transport equation, continuity equation and Poisson equation, characterized different regions electric charge. According to the variation of the electric charge, the parasitic capacitances were determined, and the model parameters obtained by linear extrapolation and curve fitting. The MOSFET model was completed in MAST language. The results obtained experimentally with Boost circuit and by Saber software simulation confirm the accuracy of MOSFET model.

Abstract: A two freedom flexure system is presented. All the constraints are selected in Case 2, type 1 and Case 2, type 2 in FACT chart. The locations of the non-redundant constraints are optimizated by change laws of the three order natural frequency with the position of constraint. All the redundant constraints are selected to increase the add symmetry to the flexure system. Results of Simulation of static calibration dominates that the flexure system is decoupled. The synthesis process of the two freedom flexure system proposes important reference for design of the flexure system.

Abstract: Chaos depends on the random parameters are explored in circuit system with ferroelectric capacitor in this article. A random parameter is considered to characterize the random factors in this kind of capacitor. After we reduce the nonlinear circuit system with random parameter into the equivalent deterministic system by orthogonal polynomial approximation, the available effective numerical methods is applied to obtain the responses of the equivalent deterministic circuit system. Then by numerical simulations, we systematically explore the effect of the random parameter on chaos, and find the intensity of random parameter can present the rich and colorful structures of chaotic attractors.

Abstract: Having studied harmonic’s impact on electronic integrator’s Calibration. The mathematics model of the integrator and the response of the integrator simulator to volt-second pulse periodic signal have been established through SIMUNLINK in the MATLAB, it theoretically analyzes the low-pass filtering characteristics of ideal integrators and the impact of pulse signal harmonics on approximate integrators. The experiment shows that the bigger the harmonics elements in the volt-second’s pulse signal is, the less accurate its calibration of integrator will be.

Abstract: For the super-size and large flexibility of Pipe Lay-down System, considering the influence on the mechanism from elastic deformation and mechanical vibration during the movements, the kineto-elastodynamics model is established by using the KED theory which is based on the analysis of kinematics. The PLS mechanism is divided into several finite elements. Dynamic equations of beam element are established in the local coordinate by using Lagrange’s equation. In the process of changing from local coordinate into global coordinate, no longer considering the instantaneous structure assumes. In consideration of the first and second derivative of the coordinate transformation matrix versus time are not zero. The mass matrix, damping matrix and stiffness matrix of the final system kinematic differential equation are the function of time. It realizes the continuity of variable in the time domain. Derivation of the results in this paper lays a foundation for the next more accurate and efficient methods being applied to solve the KED equation of PLS mechanism.

Abstract: Measurement of vibration signals were conducted in accelerating and constant velocity travelling conditions. By using time domain, frequency domain and 3D spectral array methods, the vibration acceleration of passenger’s seat, power assembly and suspension, the NVH characteristics of the pure electric bus were analyzed. On the one hand, we find that the vibration level of passenger’s seat increase linearly with the travelling speeds. On the other hand, because of the poor isolation rate of the power assembly mount and the chassis suspension, the vibration acceleration on the passengers’ seats are very great and affecting the passengers’ comfort. These experimental results will give help to further study of the NVH characteristic of the pure electrical bus.