Applied Mechanics and Materials Vol. 443

Abstract: To improve the application of Smoothed Particle Hydrodynamics (SPH) method, a new Visual Basic-Fortran (VBF) SPH model with the improvements on efficiency and visualizable interface is presented. The VBF SPH model is based on mixed language programming (MLP) method that not only improved SPH model’s efficiency, but also created the interface functions to control and observe the whole simulation. İts general structrue is to compiling the Fortran computing subroutines into Dynamic Link Library (DLL) files and these files will be called by Visual Basic (VB) programs during the calculation. Besides that an improved link-list algorithm, is described detailedly. This algorithm improves the model’s searching efficiency by reducing the number of searching cells. Two classical problems, Flood flow over Dam and Droplet-Impact, are chosen to analyze the VBF SPH model efficiency and distinguish the improvements’ effect. Both of problems are simulated respectively by VBF SPH model and VB model. According to first simulation VBF SPH model is more than 8 times faster than the VB model. And the second simulation refers that the MLP method increased about 7 times efficiency while the improved link-list algorithm increased more than 1 time.

Abstract: The signal which is generated by the dynamic balance regulator for unbalanced spindle in the process of adjustment, having strong nonstationarity. The traditional signal processing methods could not deal with these signals, but also could not express the processing of signal changes. Aiming at the problem, a method combining mathematical morphology filter and the short-time Fourier transform is applied in the non-stationary signal processing in this paper. Using mathematical morphology filter could reduce the noise of spindle vibration signal, and improve the SNR. The amplitude of spindle vibration signal could be got by means of short-time Fourier transform method. Utilized the method proposed in this paper, non-stationary signal of the spindle dynamic balance regulator online adjustment process has been analysed, the results of the experiment show the feasibility of the method.

Abstract: This paper, based on an analysis into the approaches, at home and abroad, of the conveyor belt joint monitoring, provides an in-depth investigation into the causes and conditions of the belt conveyor tension overload and fractures, finding that the fractures of the joint are random, and are among the most frequently occurring problems, along with steel-cordbelt conveyor belt deviation, drum slipping, roller life, fire, and the steel-cored belt longitudinal tearing etc Therefore, based on the fact that the joint length can be measured by detecting its tension with an senor, this paper investigates the technology of belt joint monitoring by means of the F-L curve,, so as to provide an early warning. This method the system practice shows that: the technology has good application value in production and application, has the vital significance to the enterprise safety production.

Abstract: building picking mechanical torsional vibration dynamics model, carries on the equivalent moment of inertia, equivalent torsional stiffness calculation, torsional system intrinsic characteristics are analyzed, and the programming, the Harvester power transmission system of each order natural frequency and engine low harmonic times incentive relations, so as to make the vehicle torsion effect effectively restrain.

Abstract: The man-machine dialogue can be effectively realized by developing the animated simulation of four-bar linkage with VB. In this paper, through the analysis of linkage graphics, the animation flow chart of four-bar linkage is drawn.

Abstract: Speed is the core elements in table tennis athletics, however speed is lack of strength of the attack and lethality is limited, it is only with the aid of a force and speed of rotation to achieve the kill is the most optimized techniques. From the ping-pong rotating force, to elaborate the table tennis increased rotational mechanics principle and cause analysis, through the analysis of principles, deep space to carry out the table tennis rotating mechanical three-dimensional analysis, which provides a scientific theoretical basis and practical way for the table tennis rotation technique, its techniques can enhance new active exploration.

Abstract: In track and field, triple jump is an influential and with complex technical difficulty among these track and field events. With the gradually improvement of scientific research and practice training in track and field events, their sports level also gradually improved. This paper describes the technique development and principle analysis of triple jump, emphasize the overall importance of movement rhythm and balance control in triple jump, further analyse balance control process of mechanical movement in triple jump, thus scientifically analyse both in the upper extremity balance control and timing function, which has important implications for the analysis and diagnosis of triple jump technology.

Abstract: Badminton is one of the popular sports in the world. Our country is located on the top of the world badminton list. In order to improve the player skills, we have made the following research. We have analyzed the design and the flight track of the badmintons in accordance with the aerodynamics and then establish a model. According to the hydromechanics, the stress the badminton takes when flying is analyzed, then the relation between resistance and the speed can be got. After the curve fitting, the curve fitting figure is shown to us. Finally, we simulate the badminton flight track by using Runge-Kutta method and then get the track figure.

Abstract: The use of professional structure analysis software ANSYS analyzes the strength and seismic performance for multilayer RC structure, and through the analysis of numerical simulation, the vibration frequencies of RC frame structure and mode shapes and other seismic parameters are got, combined with IDA structure collapse fragility analysis method, the safety performance of the resistance collapse of first-order structures and two modes are been quantitative evaluation, to get the axial ratio of RC frame structure and the collapse mechanism. Finally, according to the analysis of results, the structure seismic is put forward the proposals, to provide a theoretical reference for the study of structural seismic fortification.

Abstract: The self-excited vibration of machinery is a common vibration in mechanical vibrations. Mechanical self-excited vibration destroys the normal working of the mechanical device and leads to mechanical fatigue damage. If the self-excited vibration reaches to the vibration frequency of machinery, it can produce the resonance and result in the scrapping of mechanical devices. The study of mechanical self-excited vibration has great significance. According to mathematical finite element methods, this paper establishes the mathematical model of the mechanical natural frequency through the finite volume method and gives the mathematical derivation formula of mechanical devices self-vibrated frequency. The second part of the paper simulates self-vibrated process of machinery using the professional software ANSYS software. First, it establishes a three-dimensional model of the mechanical device through the pre-processing module and analyzes mechanical self-excited vibration through calculation module and gets the frequency modal map of self-excited vibration process. It studies the mechanism of the mechanical self-excited vibration combining with modern signal analysis techniques--wavelet analysis. It gets the vibration source location which provides a reliable theoretical basis for the study of mechanical self-excited vibration.