Applied Mechanics and Materials Vols. 373-375

Abstract: This paper mainly based on the coupling relationship between tribological and dynamic behaviors of cylinder liner-piston system to establish dynamics and tribology coupling model of cylinder linerpiston-piston ring, and to analyze the effect of piston skirt profile based on it, providing theoretical basis for determining the effect of piston skirt profiles to piston dynamics and lubrication performance.

Abstract: In this paper, an equivalent mechanism is obtained by means of optimal design to overcome the drawbacks of an existing brake pedal operating mechanism in a harvester. After establishing the mathematical model, we obtain the optimal design model, including the objective and constraint functions. Consequently the local optimal solutions are worked out, resulting in a solution for the applied engineering problem.

Abstract: Gun tube is a kind of thin-walled circular tube with special use. Its inner surface are loaded serious gas loading of high temperature and high pressure gas when consecutive shooting. In this paper, the assault rifle gun is taken as the research object and the FEM software ANSYS is taken as a computing platform, data of barrel dynamic temperature and stress under continuous loading are obtained. The calculation results show that, (1) The temperature field and stress field coupling effect is very obvious in the barrel bore surface; (2) Thermal shock has obvious thin-layer effect; (3) The thermal stress caused by heat load significantly higher than the bore pressure produced by chamber pressure .Model and analysis method used in this paper provides an important reference of design for the design and improve of the barrel in the aspect of heat intensity.

Abstract: Modal analysis and vibration analysis is the foundation of dynamic characteristics analysis and it is the most important methods to analyze the inherent characteristics and mode shapes of the system. In this paper, the airport tractor frame is taken as the research object and its geometric model is established by Pro / E, 10 order modal and shapes of tractor frame is obtained by ANSYS. The results showed that: the first and second frequency of the frame is avoided the engine idling, the outbreak frequency, and excitation frequency in normal driving road. The entire frame meets the requirement of the dynamic characteristics.

Abstract: The aerodynamic characteristics of ordinary vehicle have been studied by lots of scholars, while few people pay enough attention to the aerodynamic characteristics in the bottom of the car. As the requirements of regulations for the performance of the car continues to increase, Analysis of Aerodynamic Characteristics of the car is much more necessary now. In this paper , by using CFD method and getting benefit from the established CFD software, we gave external velocity field and pressure field of the car. The data was analyzed and summarized and the computational results are obtained. In the final analysis for the flatness in the bottom of the car influence on aerodynamic characteristics.This paper has done some useful attempts, and it will provide specific reference significance to the numerical simulation on design of the car in the future.

Abstract: The paper took dish-style separators spindle system as research object, established a finite element dynamic model for spindle system based on rotor dynamic theory, and then obtained vibration characteristic of spindle system considering gyroscopic effect influenced on critical velocity. The result shows that gyroscopic effect decreases the first and second order eddy frequency of spindle system by 36.2%; spindle rotating velocity meets the design requirements for a flexible shaft. The research result indicates that the method in this paper is available, and has a guide for deeper research on vibration characteristic of high speed rotation system, will reduce research expenditure and test time.

Abstract: In this study, an adjustable damping shock absorber (ADSA) for semi-active suspension was developed. Based on the theory of hydraulics and elasticity, the ways of calculating the embranchment flow rate on the series-parallel complex pipe line (SPCPL) were deduced and employed, and the detailed mathematical model of the ADSA was established by using the equation for annular laminar deformation under a uniform load. The MATLAB software was used to simulate the detailed model, and the calculated results agree well with the test results, and the results obtained provide technical support to the design and performance prediction of the ADSA to a certain degree.

Abstract: The dynamic modeling method for parallel robot based on the principle of virtual work and equivalent tree structure is proposed by taking off the platform and the chains as well as degenerating parallel robot into a tree structure, the closed-form solutions for the inverse and forward dynamics models of parallel robot are derived. The method is applied on kinematics and dynamics analysis of a representative 3-RRR spherical parallel robot.

Abstract: The results of investigation of a new phenomenon represented by the revolving of stiff rotor in elastic supports with four self-balanced pendulums are discussed in the article. The rotor is rotating with some operating velocity but the pendulums are moving with a frequency which equals one from two critical velocities of the rotor rotation connected with its linear or angular motion parameters. The procedure of mathematical models construction for system with eight degrees of freedom is offered. Dynamical interactions’ properties between partial systems with definite forms of a motion self-organization in a freely suspended pendulum group are discussed.