Papers by Keyword: Fluid-Structure Coupling

Abstract: According to the real structure and work condition of a high-flow mixed gas control valve used in recycling generating electricity project, a modal analysis model based on fluid-structure coupling system of control valve is set up. The natural frequency and mode of valve plug and stem is obtained. The structure damage diagnostic method of high-flow valve stem is put forward. According to the change of natural frequency of the valve stem to judge appearance of fracture cracks is explored. According to the amount by which the variation of natural frequency to determine the size of crack is discussed. It is the preliminary diagnosis to the damage of a high-Flow control valve stem in the special working environment, to avoid the gas leaks, the failure of valve action, adjust or commutation, etc.

Abstract: Two coupling models, the fluid-structure coupling and the acoustic-structure coupling, have been studied in this paper, in order to describe the free vibration of a fluid-filled cylindrical shell under internal pressure from two different angles. For both models, a new approach to solve the characteristic equation is presented, using the Galerkin method to obtain the natural frequency of each mode. The comparison shows the results of two models are in good agreement. Although the two models are based on different mechanical theories, the mathematic essences are confirmed to be the same, both derived from Bessel functions.

Abstract: The impact of blast load is always taken into consideration in significant pillar bearing component and protective construction. The LS-DYNA software was employed to simulate three typical concrete filled steel tubular (CFST) columns under blast load. The JHC model was used for concrete material and the MAT_PLASTIC_KINEMATIC model which accounted for the strain rate used for steel. Three section concrete-filled steel tube columns are analyzed in different proportion of distance and get the damage form of pillars and displacement of key points. The results show: In proportion to the same distance, the antiknock ability of circular cross section is better than the other two sections. Although in filled concrete damage is serious, but the steel tube columns improve the ductility of the columns. With the increase of proportion of distance, pillar deformation gradually decrease.

Abstract: This paper presents an approach for numerical optimization design of blade stacking line for fan/compressor blade. In the present method, the linear interpolation method and Constant-Volume Tetrahedron approach are developed to exchange data between a Navier–Stokes equation solver which is adopted to evaluate the aerodynamic performance and a commercial software which is used to attain the structural characteristics. Both of those two data exchange method have been demonstrates. A simple Genetic Algorithm as a robust design optimization tool is employed to achieve the multi-objective optimization. The proposed approach is then used to optimized a fan rotor blade with different optimization goals to verify the feasibility of the reliability. The results show that, the single objective optimization design can improve the aerodynamic performance or structural characteristics remarkably, but might not promote both of those performances. On the contrary, the multi-objective and multidisciplinary design can improve the aerodynamic performance and structural strength at the same time. So, it can attain higher aerodynamic performance while satisfying the blade strength requirements.

Abstract: A 1:10 tank-car 2D fluid simulation model based on the computational fluid dynamics is established, and exchange the data with tank-car vibration model while simulating. In the paper, the 2 dimension fluid-structure coupling tank-car which owns two DOF is simulated, and the affect of fluid sloshing to tank-car longitudinal vibration is analyzed through the coupled vibration experiment. In the simulation and experiment, fluid sloshing increased the tanker longitudinal vibration acceleration amplitude and slowed response time is obtained through analyzing the difference between the different volume of fluid and the relevant solid without sloshing, and the difference of longitudinal vibration between full tank and non-full tank is significant.

Abstract: The wind turbine tower is to bear wind load and work load which is brought by the rotating blades during operation. Therefore, analysis of dynamic characteristics of wind turbine tower is a complicated task in the wind turbine reliability design. The dynamic characteristic of wind turbine tower plays an important role in its vibration control. This paper presents fluid-structure coupled dynamics equations accounting for the blade wheel load and wind load applying on the tower. By the model analysis, a feasible method for evaluating the dynamic characteristics of wind turbine tower under the wind turbine wind load and the rotating blade random load is obtained. The model is verified in the 1.5MW wind turbine.

Abstract: As part of the RTRA funded EMMAV (Electroactive Morphing for Micro-Airvehicles) research program electroactive materials were studied as well as their applications as actuators for morphing wings. The aim of this research program is to study both the actuation with large displacements at low frequencies as well as low displacement, high frequency actuation. The large displacement actuation, which targets primarily the flight control, is achievable using Shape Memory Alloys (SMA) while high frequency; low displacement actuation can be achieved using piezoelectric actuators [. This high frequency actuation is especially interesting for improving the aeroelastic coupling effect inducing both noise and drag. This paper describes the construction of a prototype incorporating piezoelectric and SMA based actuation mechanisms. Furthermore, a cooling mechanism for SMAs is described aiming at improving the cycle time of the actuator. The developed prototype is to be evaluated during wind-tunnel experiments showing the influence of the actuation on the fluid.

Abstract: The validated finite element method (FEM) was applied to the calculation of local impedance of viscoelastic sample in the acoustic tube. The acoustic impedance of viscoelastic material was calculated by three methods on the basis of numerical acoustic field computed by fluid-structure coupling method and the structure itself. The comparisons of calculation results illustrate that acoustic impedance is the inherent attribute of material.

Abstract: This paper presents static and dynamic analysis of wind turbine towers which is supporting a 1.5MW wind turbine based on the theory of FEM. In static analysis, the modal frequencies of the towers are analyzed without wind load. In dynamic analysis, by the fluid-coupling theory, the dynamic effect of wind loads on the towers is calculated. It can be concluded that the main errors under the different load situations is caused by the impact of fluid structure coupling.

Abstract: This paper proposes a novel approach for micropump driven, namely laser shock wave, with the advantages of high energy efficiency, remote control and wireless energy supply. The pump used here has the characteristics of simple structure, easy fabrication and low cost comparing to the traditional micropump. Firstly, a valveless micropump was designed and then manufactured through lithography and bonding. Secondly, modal analysis of the fluid-structure coupling system, i.e. micropump, was calculated, and the first natural frequency was chosen as the frequency of the laser pulse. Finally, experiments were done to validate the feasibility of the driving mode. Results show the new driving mode works well and may provide an alternative approach for microsystem driven.