Applied Mechanics and Materials Vol. 709

Abstract: This article reviews the experience of modeling and evaluation stability of braced shell with elastomeric bearing under static, seismic and extreme loads.

Abstract: Lip seal, widely used in industries, is usually applied to seal pressure chamber. Leakage of lip seal has always been a primary problem. In the present study, hydrodynamic property of lubricating film and elastic deformation of sealing lip are analyzed numerically by coupling Reynolds equation and elastic deformation equation. A numerical model for calculating leakage is proposed, results of the analysis will be of help to interference design and structure optimization for auto water pump bearing’s seal.

Abstract: The paper uses modern control theory and mechanical and structural vibration theory to study a mass-spring system of three degrees. Using Newton's first law analyzing the force of the object, drawn the simulation diagram from the control perspective. Reflecting all changes of the independent variables and their relationships. And revealing the characteristics of the system. We also analyzed the system can not only be controlled but also can be observed, understanding the inherent nature of the system further. About the dynamic characteristics of the system, we use the main formation method to calculate the natural frequency, the main formation and displacement response of the system^[1].

Abstract: As the most important part of wind turbine, the aerodynamic properties of blade have crucial influence on wind power generation. In this paper, the blade of 750KW wind turbine is designed in Wilson method. Actual spacial coordinates of blade sections are obtained based on space coordinate transformation theory of points. Then the blade model is created in SolidWorks by these coordinates. In this method, the modeling efficient of blade surfaces could be improved, and following aerodynamic analysis could be conducted based on this model.

Abstract: The lubrication state of three-lobe bearing is simulated by using Reynolds equation. It concluded that the load-carrying capability of three-lobe bearing increases with the eccentric distance between the centers of axis and bearing with a nonlinear way. The largest bearing load-carrying capacity occurs in the eccentric direction of 30 °and making sure the eccentric direction can improve the stability of the system. To improve the rotation speed of the axis is beneficial to promote the load-carrying capacity.

Abstract: The purpose to optimize the ship structure is to obtain the minimum weight and the maximization of economic benefit. The way is to change the ship size, structure form, whole or partial structure layout under the condition of meeting the requirements of mechanical properties. The whole ship structure optimization model is established. Optimization is carried out by means of the Optimtoolbox in MATLAB, with the total mass of the ship as objective function, the requirements of the specification and the natural frequencies as constraint conditions. With sensitivity analysis,the thickness of bottom plate, deck, keelson, side keelson, superstructure bulkhead, hatch coaming and other components are selected as design variables. The results show that through optimization, better ship lightweight effect is obtained under the premise of guarantee hull structure strength, stiffness and dynamic characteristics. The bulk carrier structure is optimizaed.

Abstract: The behaviour of granular materials especially under dynamic loading has been under investigation for years. In recent years, the advancing computer technology makes it possible to model complicate behaviour under different loadings. In this review paper, major advances and researches in the field of providing conceptual model for behaviour of granular materials have been reviewed. The reviewers have tried to categorise the researches in term of their approach to modelling the mechanical behaviour of granular materials and then identify the gaps to provide ground for the future researches.

Abstract: The singularity, namely, the output movement of the mechanism is uncertain due to kinematic bifurcation at the singular position, is the intrinsic characteristic of mechanism, resulting in movement out of control. To find a practical solution for this vexed question to make mechanism able to avoid its singular position is the greatest challenge in the field of mechanism. Based on the study of the planar four-bar linkage with singularity, the ideology of introducing self-adaptive mechanism theory into the solution of avoid singularity problem is firstly put forward in this paper. Using self-adaptive mechanism to complement the out of control parameters of singular position can make the mechanism have the ability to avoid singularity. Then the mechanism passes through the singular position smoothly with determined movement and load capability. Finally, the purpose of avoiding singularity is achieved.

Abstract: Adjusting method of traditional PID controller is complicated. The controller obtained by adjusting method of traditional PID may be not optimal. Therefore, present paper utilized the genetic algorithm to optimize the PID controller parameter of roll channel of quadrotor UAV. According to the feature of lateral stability control model of quadrotor UAV, ascend time of system, steady state error, and weighted overshoot are chosen as objective function. In order to obtain the better control effect, penalty function is used to limit the oscillation of system. Simulation results show that PID controller designed by the genetic algorithm possess the excellent flexibility, adaptability and can produce the better control effect.

Abstract: Design the experimental system of variable pump based on LabWindows/CVI’s software platform. Adopted universal design standards, the pump station can satisfy not only the variable pump performance experiment but also other components and subsystems. On software, we adapt database to administrate customers; use DLL to solve the communication between PCI cards and the application program; analog acquires by multi-channel interruption acquisition; process the experimental data to obtain the final report.