Advanced Engineering Forum Vols. 2-3

Abstract: A numerical analysis method for fluid-structure interaction (FSI) to analyze engine blades dynamic response was presented. Fluid-structure interaction is an important research field. It is mostly studies the interaction between the influence upon the fluid by the deformation of the solids, the important characteristic of fluid-solid interaction mechanics is the fluid-solid interaction between the both phase mediums. The solutions of strongly coupling and weakly coupling were discussed firstly in this paper. We compared the advantages and disadvantages of the strongly coupling and weakly coupling. And using numerical analysis method based on weakly coupling, we established a fluid-solid interaction control equation taking solid and fluid as a unified mathematical model. And we study about blades deformation and displacement under the action of air loading in engine. Using computational structural dynamics (CSD) calculate the displacements of blades, and using computational fluidic dynamics (CFD) calculate the pressures of blades, completing the fluid-structure interaction analysis in engine blades by iterating this two values(the displacements and the pressures) until the computational convergence solution is obtained. At the end of this paper, the model of fluid-structure interaction and the simulate procession of the numerical analysis method were presented. Based on the analysis, the simulation result is qualitatively discussed referring to the factual conditions of the engine for validating the feasibility of analysis method.

Abstract: The dynamic model of a rotor system of assembled compressor is established. Based on the single axis analysis, and considering the tilting-pad bearing stiffness characteristics with speed variations, the paper analyses whole system’s nature characteristic with gearing mesh factors. It mainly expands with the form of amplitude-frequency drawing and spectrum charts, and examines the dynamic response with each key position of coupled systems under the two working conditions. The results show that, because of the existence of gear meshing effect, Low speed axis and high-speed axis in the corresponding speed shaft appeared a few larger vibration amplitudes, at high speed axis add unbalance force, can arouse resonance of this axis in the first two order critical speed, but in the other axis don’t have obvious display.

Abstract: Based on elasticity plate theory and the theory of viscoelasticity, the solution of the natural frequency and dissipation factor are given under different boundary conditions. In this paper, the differential equation of the cylindrical shells is set up based on Love shell theory. Then the transfer matrix method is introduced to calculate the entirety transfer matrix and the expression of different frequency and dissipation factor. At last the natural character of CLD cylindrical shell under two different boundary conditions is researched.

Abstract: A kind of new steel coil upender clamping device was designed. The model was set up by use of SolidWorks and the reliability analysis and motion simulation was further performed in ADAMS. Because of risk at steel coil upender, once the accident appears, it gently slowed-up production and damaged the device, and it could cause people’s dying vitally, it is especially important to assure the longtime work and safety of device which we studied on. The results showed that the efficiency of turnover process of the device was high and the system could save driving force. These also provided some theory bases for the design of the device.

Abstract: Using the function of static analysis and modal analysis of ANSYS software, the bearing capacity and vibration condition of high-rise buildings can be simulated and analyzed, and the safety for the design of high-rise steel structure can be ensured. This research is mainly aimed at modal analysis for the overloaded five-layer vertical structure platform, and proves the rationality of the structure design by analyzing the conclusion. The analysis content includes: the stress that structure platform is in the static load, the analysis results include analysis parameters such as stress, torque, strain; modal analysis of structural platform, and the analysis results are respectively outputed in forms and pictures. Through the analysis, it can be proved that the structure platform is designed reasonably, and can satisfy the requirement of actual production.

Abstract: The contact problem between root-blade and slot-disk structure of compressor is of much importance, because there is serious stress concentration in the structure, which is one of the parts with multi faults in aero-engine. First, finite element model for dovetail attachment is established to analyze stress concentration effects. Then, the stress distribution and other parameters such as contact pressure is obtained through contact analysis. In this paper, the finite element method based on contact analysis is used. Calculating results show that equivalent stress, contact pressure of blade-disk structure increase steadily as the rotating speed increases.

Abstract: The relationship of the kinetic fundamental parameters for both the prototype and model are derived by employing the finite method. Based on the relations, the scaling laws of the thin walled cylinder for the free vibration are found by applying the similitude transformation to the governing equation. In the absence of the experimental data, the validity of the scaling laws is testified by numerical data. This is done by calculating theoretically the natural frequencies for free vibration of the cylinders. By substituting the model frequencies in the scaling laws, the frequencies of the prototype are obtained. Consequently, the frequencies of the model and prototype are compared. Examples that one end of the thin walled shell is clamped and the other is simply supported show exact agreement.

Abstract: Although the gyroscopic effect on rotor system has been noticed for decades, it is often underestimated and even ignored in the simplified model; moreover the comparing analyses of it on dynamics of rotor system with distributed masses are rarely performed. In this paper, a model of dual-disk rotor system with 8 degree-of-freedoms is developed to show the gyroscopic effects, especially on asymmetric rotor system, in which the polar and transversal moments of inertia of the disks are incorporated. The critical speeds and unbalance responses of such a rotor system are simulated numerically and compared respectively in 4 different asymmetric cases, including 2 cases of position asymmetry and another 2 cases of support stiffness asymmetry. The analysis results clearly show that the gyroscopic effect has obvious influence on the critical speeds and unbalance responses under different asymmetry conditions.

Abstract: An analytical solution is deduced for a three-dimensional transversely isotropic axisymmetric multilayered circular plate made of piezoelectric (PE) and piezomagnetic (PM) under simply supported boundary condition. The state space vector, finite Hankel transform and propagation matrix methods are utilized together to obtain the full-field solutions for the multilayered circle plate. Numerical examples for five-layered PE/PM composites with dimensionless frequencies of the multilayered plate under simple-supported lateral boundary conditions are presented. The frequencies increase with the ratio of the thickness to radius.

Abstract: Based on mechanical properties of rotor nonlinear vibration and the assumption of large deformation, the rotor nonlinear vibration model in the form of Duffing equation is constructed from typical engineering problems. According to analytical solutions of Duffing equation, system’s equivalent frequency and frequency response equation are derived. Furthermore, the influences of stiffness, damping and nonlinear components are studied. The single-disc rotor nonlinear vibration experimental results verify the rationality and efficiency of nonlinear vibration model’s construction and Duffing equation’s analytical solution and frequency response equation. The mechanisms of resonance, amplitude jump and hysteresis are also revealed. It provides a new research method for rotor vibration characteristics analysis.