Advanced Materials Research Vols. 945-949

Abstract: Based on UG and Automatic Dynamic Analysis of Mechanical System (ADAMS), the 3D model of differential was constructed and the real-time dynamic simulation of differential was achieved. The effects of gear backlash between half axle gears and planetary gears on the vibration of differential are studied. To increase the credibility of simulation results , the contact forces between half axle gears and planetary gears were calculated based on the Hertz elasticity impact theory.

Abstract: In this paper, the noise of gear transmission system of the type, source and mechanism is summarized and analyzed. The method of noise control was put forward according to the mechanism of noise of gear system. Put forward reasonable Suggestions For gear type and material selection in the design of gear transmission system, the gear parameters, processing technology, cabinet design, gear train assembly, gear modification, the lubrication mode. For gear system optimization design has a certain guiding significance.

Abstract: In order to conduct dynamics simulation analysis on an airborne electronic equipment, total mass equivalent method is used to simplify the finite element model of electronic building brick. Considering this method’s disadvantage that it does not take into account the effect which the components have on stiffness of the printed circuit board(PCB), the modal test technique is carried out to recify the model and generate the equivalent stiffness of the substrate. Then the modal analysis and random vibration analysis are performed on the complete machine, calculating more accurate dynamics simulation results which provide a reliable qualitative basis for improving the vibration-proof design of the equipment.

Abstract: Sound pressure is an important parameter of marine background noise monitoring. A laser interferometric hydrophone is designed based on Michelson interferometry. By tracking compensation method, immunity from interference of the hydrophone is improved. Error analysis shows that the vibrating membrane is the main source of the sound pressure error, which can be eliminated to a certain extent by a vibrating membrane materials selection. Offshore data show that hydrophone pressure measurement of high precision, and with a good frequency response. By comparison with the theoretical model to some extent also verified the accuracy of data. In coastal waters, wind noise and ship radiate noise is the main noise source of marine ambient noise. Here, marine ambient noise spectrum of three wind speed were calculated, and with Kundsen curves were compared. Results show that measured data and Kundsen curve fitting is better. In addition, the measurement of vessel radiation noise is mainly concentrated in frequency range of 350~500Hz.

Abstract: In recent years, the Low speed two stroke diesel engines are widely used as the main power device of big ship for its so many advantages such as the high power, better economical efficiency and good maintenance. However, the problem of diesel strong vibration and noise becomes a more and more serious at the same time. Because of the Construction Features of marine two-stroke low-speed diesel engine, the structure has to be suffered different kind of forces when it runs. In considering the source of vibration, the whole noise can be divided into combustion noise、machinery noise and aerodynamic noise. The combustion noise caused by cylinder pressure is the most important part of diesel noise. In this paper, the cylinder pressure curves are tested. The internal combustion engine dynamics and the equivalent node load are used in the calculation procedure to achieve the real condition simulation. The loading program is made to simulate the change of cylinder pressure and the move of piston. The transient response of the diesel engine is calculated. The characteristics of diesel caused by cylinder pressure are analyzed.The response analysis can be used to the vibration control.

Abstract: To grip control mechanism of plate structure radiation noise, a method to calculate radiation resistance was improved based on series approximation, by which the analytical solution of acoustic features were derived. And then the effects of the mutual-modal coupling were investigated in studying vibro-acoustic characteristics of a simply supported plate. Some conclusions have been given, such as the relationship between the radiated noise level and the space-time distributing, fundamental principles and measures of altering the space-time distributing, which supplied the academic and applied foundation for noise control.

Abstract: The reaming process with rigid single blade reamers boring is one kind of deep processing methods which develop rapidly in recent years,which has a series of advantages such as high-speed cutting, auto-oriented, low surface roughness and so on.Appear as one kind of precision hole processing technology in the deep hole processing currently,and shows the superiority of processing.The self-excited vibration is a common phenomenon in deep processing,and seriously affect the stability of hole machining and processing quality.It performance very obvious in rigid single blade reamers boring processing,and has a certain degree of particularity. Established as a mathematical model of the rigid boring reamerThe analysis of mechanism of Self-excited vibration in reaming processing of single blade rigid boring reamer, and the study the impact of the friction characteristics of the guide block and the hole in self-excited vibrations,provide the basis for the inhibition of self-excited vibration.

Abstract: Normally, the workover rig platform is obtained only low order natural frequency by modal analysis. In order to understand the frequency response of structure dynamic load, we well carry out harmonic response analysis on the operation platform in this paper. On this basis, determine the modal frequency that is greatest effect on dynamic behaviour of the workover rig operation platform structural system. To extract the modal frequency as dynamic optimization goal or state variables.Finally, achieve forecast the possibility of dynamic interference between operation platform and other components.

Abstract: The whole engine model，including intake system, coupling with exhaust system, is established by the software GT-POWER. Through the parameter change of tail pipe geometry, it is analyzed in this paper how the tail pipe geometry affect tail pipe noise. With the test data and the simulation calculation results, it analyses the influence of the tail exhaust pipe length, diameter, shape, terminal bending angle on engine performance and tail pipe noise, so as to choose suitable design parameter of tail pipe to meet the requirements of engine performance and the tail pipe noise.

Abstract: Firstly, according to the structure characteristics of precision centrifuge, the mathematical model of its dynamic balancing system was set up, and the dynamic balancing scheme of double test surfaces, double emendation surfaces were established. Then the dynamic balance system controller of precision centrifuge was designed. Simulation results show that the controller designed can completely meet the requirements of precision centrifuge dynamic balance control system.