Applied Mechanics and Materials Vols. 229-231

Abstract: A simple approach to reduce the governing equations for thick honeycomb sandwich panels to a single equation containing only one displacement function is proposed in this article. The variational equations of motion are derived using Hamilton’s principle and by introducing differential operators. The exact solution of the natural frequencies for rectangular honeycomb sandwich panels with all edges simply-supported is obtained and leading to a satisfied agreement with theoretical results. The influence of the ratio of core thickness to face sheet thickness and aspect ratio on the natural frequencies is studied. The analysis results demonstrate that the presence of inertia of rotation will decrease natural frequencies, and the aspect ration changes not only the value of natural frequencies of the sandwich panel but also the mode order.

Abstract: It is very significant for the vertical axis wind turbine to design the best support structure with high strength and stiffness. This paper discusses modeling a kind of tube tower structure of the vertical axis wind turbine and carries out static and modal analysis based on the finite element method. The static and modal characteristic of tube tower such as stress, strain and mode shapes are obtained accurately which can provide basis to optimal design the support structure for vertical axis wind turbine.

Abstract: The mistuning of periodic structure was generally considered to be natural parameter mistuning, such as stiffness mistuning, damping mistuning and mass mistuning. However, in engineering practice, there was another kind of mistuning—force mistuning. Based on a typical concentrated parameter model of periodic structure, the vibration characteristics, such as natural characteristic, vibration mode and vibration localization of periodic structure with different mistuning forms, were compared and analyzed. The results show that, as a new mistuning form, force mistuning won’t bring mode localization, while it could lead to vibration response localization. The results are very important for periodic structure design and manufacture.

Abstract: The optimization research of process parameters for big power Laser cladding valve parts, is a research focus of modern surface hardening technology. The article discussed in detail for solving the optimum process parameters of Laser cladding for the selection approach of strategy of genetic algorithm, the quantitative relationship model was established between process parameters and the valve parts property using neural network method , which process parameters are laser power (P), scanning speed (V), powder feeding rate (G), scan spacing (D) and thickness ( ) etc., the best configuration program of Genetic Algorithm control parameters has been obtain by means of the parameters encoding、initial group setting、fitness function design,genetic operation design and algorithm control parameters setting. The optimization of process parameters is obtained to fit the Laser cladding technology by using genetic algorithm toolbox in the MATLAB environment, and the optimization goal of the valve parts property has also been achieved. Practice has proved that the optimal process parameters are correct by the genetic algorithm , and has a very good production practice guide.

Abstract: In this paper, the finite element software was used to analyze the rigidity of the pump body and the rotor shaft, in order to provide some useful information for the optimal design of pump. The analysis result shows that the rigidity of the pump body model is adequate, but the rotor shaft displacement is a little large, which should be modified. Nomenclature F Centrifugal force of the impeller [N] m Quality of the impeller [kg] w Rotational speed of the impellor [r/min] r Effective radius of the impeller [m] F1 Force on one bearing block [N] M Bending moment on one bearing block [N*m]

Abstract: This paper studies the different porosity of porous medium how to affect the flow velocity field under the conditions of same inlet velocity and fiber diameter by CFD method. Geometric model of the catalytic converter has been established and meshed by the pre-processing tool FLUENT. The flow speed simulation filled contours and velocity distribution curve of the fiber porous material show that reducing properly the porosity may improve the uniformity of the velocity in Y and Z direction of the porous material. The less porosity is beneficial to exhaust catalytic reaction.

Abstract: Ball-type automatic balancers have been applied successfully to suppress unbalance vibrations of a rotor. A traditional ball-type automatic balancer consists of several balls moving along a fixed circular orbit. A new type of balancer, the ball-rod-spring balancer, in which the ball may move in the radial direction as well as in circumferential direction, has been proposed. This study aims to compare the performance of the new type of balancer with the traditional ball-type auto-balancer.

Abstract: From three ways of the temperature gradient, the change rate of indoor temperature and heat flux, contrast analysis the cooling effect of three cooling devices on the capillary tube, cooling ceiling and radiant floor, the conclusions could be obtained. The average of vertical temperature gradient in simulated room is equal to 1°C/m, which meets the requirements of human thermal comfort. When the temperature in simulation room falls from 30°C to 26°C, the temperature drop velocity for cooling ceiling is the fastest. The heat flux of the cooling ceiling is maximum, the second one for the capillary tube, and the least one for the radiant floor. Thus, the cooling effect of cooling ceiling is the best.

Abstract: According to characteristics of WN gear multi-point meshing and double-arc tooth contact, the finite element analysis model of the WN gear drive is established by Pro/E and ANSYS modeling techniques. The contact way and meshing feature of the WN gear under the different conditions and parameters are studied by three-dimensional dynamic meshing simulation analysis of gear drive. The analysis model of contact strength at loading driving is established by three dimensional geometric contact characteristics and elastic deform theory. Impact of helix angle and center distance error in the calculation of WN gear contact strength on maximum contact stress is analyzed. The results show that increase of the helix angle and a slight decrease of the center distance can improve the contact strength.

Abstract: This article describes the history of the development of structural damage, and an overview of current research status at home and abroad based on modal analysis of structural damage identification, reviewed in recent years the structure of the early damage recognition technology, from the application point of view of definition of indicators and indicators on the current some indicators of a comprehensive analysis and evaluation, further analysis of the feasibility of several modes of indicators to identify structural damage diagnosis, pointing out that the modal parameters of structural indicators to the validity and accuracy of damage identification and the need to further address the problem. The research will provide a reference for the application of modal analysis method to detect structural damage diagnosis in order to ensure early discovered the damage and accurately identify the site of injury repair in a timely manner.