Applied Mechanics and Materials Vol. 251

Abstract: The indirect coupled modeling of the metal base disrepair has been carried out by software ANSYS. Results show that diagonal tensile stress is the main factor of crack, crack easily take place in the lower surface, where obviously exist a region of stress concentration in 45°direction. It should make symmetrical and uniform distribution as much as possible

Abstract: This paper develops an automatic nested agglomeration methodology for 2D multigrid flow solutions over anisotropic unstructured grids. The algorithm combines isotropic quadtree based coarsening and anisotropic directional agglomeration method to yield a desired coarsening ratio and high quality of coarse grids, which works on cell-centered finite volume scheme. This coarsening strategy developed is presented on an unstructured grid over the RAE2822 airfoil. It is shown that the present method provides more suitable coarsening ratio and aspect ratio at all coarse grid levels than only quadtree based coarsening method.

Abstract: Centrifugal fan is a kind of widely used turbo machinery. It is widely used in buildings, mines, factories, tunnels, vehicles, ships and air cooling towers and cooling; grain drying and sending; inflatable hovercraft and propulsion. It has many advantages compared to axial fan. In this paper, we study the numerical simulation of the whole flow field of a High-pressure centrifugal fan called 9-16№15.9D.The researches can contribute to a better design on centrifugal fan.

Abstract: To the shortcomings of neural network in fault diagnosis, such as multiple input dimensions and the huge amount of data, some reductions from data based on rough sets theory are derived and unessential attributes were eliminated, an optimized rough set-neural network intelligent system was established. Through analyzing for instance, the time of fault diagnosis can be reduced by using the system, and a new idea was provided to diagnosis of high reliability equipments.

Abstract: A solar cells test system that can be used in the natural environment is designed, which can complete a variety of test experiments on different types of solar cells under different environmental conditions. In the testing process, the basic properties of solar cells are given and recorded in real time. Since installed and operated, the system works stable. Experimental results show that the test system has high accuracy and repeatability, and in line with the requirements of solar cells testing.

Abstract: At present, the profile in the impeller axial plane of the engine water pump is designed by using the method of the projection on the axial plane, which needs repeat calculation and plentiful and complicated works. The profile in the impeller axial plane is designed by the design method of the hyperbola profile according to the principle of the angle flow which follows liquid flow law. This way provides a simple and available method for the engineers that embark on the impeller design. It can avoid the complication of conventional way and save large amount of manpower and funds. The model is built by CAD and analyzed by CFD. The result shows that the reversed flows and the secondary flows are evidently reduced. At the same time, the experiment verified that the head and efficiency of the pump are improved distinctly.

Abstract: Coupler’s energy absorption part is made up of elastic buffer and crushing tube. Elastic buffer is used to absorb impact energy produced from locomotive’s normal running process while the crushing tube is used to absorb the ones produced from accidental impact process. It is one of key problems to solve in locomotive’s impact simulation process that to establish and manage the coupler’s equivalent model. The article simulates coupler’s absorbing of energy in impact process at two operating conditions. According to the relative energy absorption design standards, the article evaluates the correctness of the established coupler’s equivalent model. The simulation result indicates that the established coupler’s equivalent model satisfies the design requests.

Abstract: The technology of flywheel energy storage is already widely used in motorcar, electric power systems, spaceflight and martial fields. Decreasing the weight, increasing rotating speed and strength of the flywheel rotor and improving the energy storage efficiency of the flywheel are always attention-getting. In this paper, a flywheel energy storage is designed and finite element analysis is done to obtain the stress distribution of it before being produced. The maximum and variety of radial stress and circumferential stress are studied and the influence of composite material wrapped on flywheel rotating at high speed is discussed. Then the action of composite material to stress concentration around the small hole on the hub is thought about. The results of this analysis can prepare a valuable guide for flywheel energy storage at design and manufacture stage.

Abstract: Peak is one of the important parameters of pressure, so a pressure measurement appliance for peak based on FPGA and SCM is designed, including pressure sensor, sampling circuit, signals de-noising process, data processing and liquid crystal display circuit. The stress signals are converted into voltage by pressure sensor, and are sampled through high precision AD, then FPGA de-noising these signals through wavelet , last, signals are transformed to the micro-controller, peak value is got with the sampling data processed by SCM, and finally display peak value in LCD screen. The feasibility of the peak measurement appliance is verified according to the simulation by proteus.