Applied Mechanics and Materials Vols. 397-400

Abstract: The performance of internal combustion (IC) engine is influenced by the characteristic of the intake process. The intake process of is very complex because the pressure waves transmission and reflection lead to pulsation and resonance in the pipes. The intake quality is directly related to the structure size of intake ports. The objective of this study is to use a one-dimensional simulation methodology to optimize the intake ports structure of a four-cylinder gasoline engine equipped with turbocharger and intercooler. Steady-state simulation was performed and the results were verified by the experiment data. The impact of the structure size of intake ports on power performance was identified and analyzed. The length of intake ports influences the pressure wave in the intake ports, and then the volumetric efficiency was impacted. The length of the intake port is inversely proportional to the resonance frequency, which means the longer the pipe is, the smaller the resonance frequency is, and then the lower engine velocity the resonance point moves to. This analytical methodology has significant advantages and can be applied to optimize the structure and the performance of the engine.

Abstract: For the problem of one time trajectory correction, a new correction mechanism changing the resistance pieces area is given. The projectile motion locus can be controlled by increasing resistance. In view of the issue of correction trajectory of flying body, the aerodynamic characteristics are changed by the size of resistance ring unfolded area. The comparison between resistance ring flying body and ordinary flying body has been analyzed about the three-dimensional flow field in different sonic. This paper researches related variation and factors of the aerodynamic characteristics with the size of resistance ring unfolded area as a characteristic parameter. The changes of the size of resistance ring unfolded area have a significant impact on resistance coefficient of the flying body. Damping plate affects the part flow field of the flying body and then the whole flow field. On the leeward side of damping plate, there forms the obvious whirlpool area. Due to the low pressure of the whirlpool area, there brings the pressure difference between windward and leeward of the damping plate, and this situation exists in the conditions of subsonic, transonic, and supersonic.

Abstract: This article is based on the concept and the calculation method of polar moment of inertia to derive the calculation formula for polar moment of inertia of rectangle spline shaft and involute spline shaft. Then verified the correctness of the calculation method and laid the foundation for the strength calculation of spline shaft.

Abstract: The conservation principle of energy and the mass center movement theorem of rigid body and the moment of momentum theorem relative to the center of mass were used to study the dynamic problems of the eccentric cylinder on the inclined plane. The mass center velocity and the acceleration of the cylinder and the normal pressure and the friction force of the cylinder acting on the inclined plane and etc are given. An example is introduced to show the variations of the physical variants, and the numerical results agree with the theoretical analyses.

Abstract: This paper investigates the suppression of vibration and noise radiation in a flexible isolation system through the use of periodic layered structures. A single-stage vibration isolation model is developed first. Then, the isolation performance of the periodic structure is studied. Furthermore, the influence of the isolator location and the phase difference on the radiated sound power of the foundation is investigated. The numerical results show that the vibration and noise can be greatly attenuated in the band gaps.

Abstract: It is very important to control mechanical press slide height precisely when it works because it will lead to loss of stamping accuracy while the slide height error appears. The paper designed a novel controlling device based on linear encoder to adjust slide height dynamically. Equipped with high-precision linear encoder on the mechanical press slide, the height of slide measured by micro-controller real-timely, the device drives the controlling motor to adjust the position of slider if slide height error occurs.

Abstract: Mechanical model of crankshaft and connecting rod mechanism of reciprocating compressor was built. Then the order of stress was obtained every ten degrees while crankshaft turning. The larger stress of crankshaft initial turnings was utilized to calculate the whole model and the unreliable region and destructive working condition then was determined. The situation was simulated with ANALYS and the static characteristics, i.e. stress and strain, of the crankshaft was also obtained. The simulated results testify the analysis and the results of the paper have great value for reference when designing crankshafts.

Abstract: Dynamics characteristics of SINS damping system in shock environment were analyzed by finite element method, as the deformation of dampers may leads to the accuracy loss of SINS. In addition, the influence of absorber stiffness and damping coefficient on dynamics characteristics were studied. The results indicate that the decoupling of vibrations is significant for the accuracy of SINS. However, considering the almost impossible of completely decoupled vibrations, its necessary to carry out an optimal design of the absorber stiffness and damping coefficient to maintain the accuracy of SINS while meeting the requirement of vibration isolation.

Abstract: The non-linear response of a rotor supported by active magnetic bearings (AMB) under multi-parametric excitations is investigated. The method of multiple scales is applied to analyze the response of two modes of a rotorAMB system near the primary resonance case. The steady-state response of the system is studied numerically, applying the frequency response function method. It is shown that the system exhibits many typical non-linear behaviors including multiple-valued solutions, jump phenomenon, hardening non-linearity. The effects of the different parameters on the steady state solutions are investigated and discussed.

Abstract: The method of transfer matrices used for torsion vibration of ships complex shafts was analyzed, and various simplified models of transfer matrices were obtained by building a hybrid model for lumped parameter elements and distributed parameter elements. Based on the above, verified by an example of a complex shaft with one propeller driven by two turbines, the method of simplifying model was provided by analyzing the calculation results on the different simplified models.