Abstract: Grasping the transmission of side thrust of piston is one of the effective methods to control engine vibration and noise. The paper uses time-domain FEM to study engine vibration. Firstly the finite element model is established after simplifications and modal analysis is conducted. Then the side thrust of piston is calculated and applied to cylinder liner using equivalent nodal load. The surface vibration is gained, from which it can be concluded that the displacements of upper block and top cylinder head reflect changes in cylinder pressure, while the vibration of observation window is complex. Finally, the vibration in a variety of engine working conditions is analyzed. Under load characteristics, the amplitude of engine surface vibration changes with loading; under propulsion characteristics, the surface vibration is essentially the same.
Abstract: The performance of twin-screw compressor is mainly decided by profiles of the two rotors. The constitution of new rotor profiles is studied, meanwhile the key technology of generating rotor profiles are mainly studied in this paper. A new method based on forward and reverse direction for generating rotor profiles with meshing lines is proposed.
Abstract: MAV- Micro Air Vehicle which acts like bird has attracted many studies because of outstanding aerodynamic property. Former studies on birdlike MAV with flapping wing had just focused on the flapping motion, but passed over the change of flapping angular velocity and deformation of wing, therefore lost the good aerodynamic capacity. One new mechanism of the birdlike MAV is designed and studied. The mechanism can bring out 3 motions at one time, including flapping, spanning and twisting, so has movement as bird. The kinematic performance including the flapping angle, flapping angular velocity, and the folding angle etc., has been studied and compared with other relative works. The design can help the birdlike aircraft into reality.
Abstract: Sliding and plowing are discriminated based on Hertz contact, and the grain number statistics model is established considering that grain size and abrasive protrusion height fit normal distribution. The analysis shows that less than 5% of grains are contacting with workpiece in the grinding arc, about 96% of contacting grains plow and about 4% cut. Sliding grains accounting for contacting grains is about 0.2%, which is almost negligible.
Abstract: With a design of the box girder of bridge crane for the rectangular right track girder, rectangular side rail girder and two trapezoidal side rail girder, MATLAB optimization tool is carried out to calculate the discrete variable by homing method one by one. Then the discrete variable which is the thickness of the steel plate used in box girder is used to determine the shape of the cross-section of box girder.
Abstract: The tightness of interior space in condition of a high speed train with its side door, side window closed called train air-tightness. The paper introduces the air tightness of the high speed train and the basic methods for air tightness testing. It also applies a constant pressure leak model to test and points out that the importance of air tightness for high speed train.
Abstract: By analyzing the current structure of biomass carbonization devices; the advantages and disadvantages of current devices are summarized. Aimed at the problems founded out, the carbonization furnace structure is improved. The designed new carbonization furnace not only solves the exist problems to some extent, but also has some reference values for the future carbonized stove design.
Abstract: The 3D model of machine tool column of NC gear shaper is created in Pro/E. This model is imported into the HyperWorks by STEP file. The column structural static stress and deformation, the five-step modal natural frequencies and mode of vibration are obtained by Hyper Works static and dynamic analysis. Based on the analysis results, this study offers a kind of reference comments for the design and improvement of machine tool column of the gear shaper.
Abstract: There is a common problem during kill a well, which is how to quickly and accurately control the surface casing pressure according to the requirements for killing a well. A step-by-step exploration process is employed on operation sites. Continuously adjusting throttle valve to acquire surface casing pressure may lead to failure of kill operation because of its long time and low control accuracy. Obviously, if the calculation problems of throttling drawdown can be resolved,the relationship between drawdown and throttle valve opening can be found and the course of explorating can be converted into a straight course.Then the success rate of killing well can be improved. More importantly, this can make automatic controll of surface casing pressure possible. The paper built the calculation method of throttling pressure drop by theoretical analysis and verified the calculation method by adopting it into field test. The result has showed that the calculation method of throttling pressure drop coincides with experimental results and it can be used in engineering practice.
Abstract: The four ring-plate-type pin-cycloidal gear planetary drive is a new type of the cycloid. Use the new repair tooth profile gap mesh analysis method to Calculate the cycloid mesh stiffness. the mesh stiffness of the cycloid is solved, According to simulation results based on the ANSYS / LS-DYNA. and the results were compared with theoretical calculations, both mutual authentication. It can be use to improve the prototype program at last.