Applied Mechanics and Materials Vol. 307

Abstract: Microgas flow analysis may not be performed accurately using the classical CFD methods because of encountering high Knudsen number regimes. Alternatively, the gas flow through micro-geometries can be investigated reliably using the direct simulation Monte Carlo (DSMC) method. Our concern in this paper is to use DSMC to study the mixing of two gases in a microchannel. The mixing process is assumed to be complete when the mass composition of each species deviates by no more than ±1% from its equilibrium composition. To enhance the mixing process, we focus on the effects of inlet-outlet pressure difference and the pressure ratios of the incoming CO and N₂ streams on the mixing enhancement. The outcome of this study is suitably discussed in the result section.

Abstract: This paper focuses on the development of a predictive model using the measured forces acting on the cutting tool during turning operation of AISI 1045 Steel using a Tungsten Carbide cutting tool insert. On the basis of the experimental results, second order mathematical model is developed in terms of machining parameters by using the Response Surface Methodology (RSM). The results are analyzed statistically and graphically. It has been observed that the predicted values using RSM also follow the same trend as given by the measured values.

Abstract: This paper focuses on finite element modeling of orthogonal cutting process of AISI 1045 steel using Modified Johnson Cook (MJC) as constitutive material flow model under various machining parameters. Finite element solutions of cutting forces, effective stresses and temperature are obtained for a wide range of cutting speeds and feeds. The effect of feed and cutting speed on cutting forces, effective stresses and temperature has been studied over a wide range of values. Percentage variation of each is also studied to predict co-relation with the different machining parameters.

Abstract: In this paper steady streaming due to a sphere has been studied. Instead of using matched asymptotic method we are applying Vishik-Lyusternik method. In this paper we consider the situation when the sphere is at rest and fluid oscillating at infinity. Results have been obtained for Re=O(1) . Effect of Stokes drift is also calculated for the fluid particles.

Abstract: Bolt joint has an important influence on the dynamic characteristic of guide rail. Linear rolling guide is chosen as the research object in this paper. Firstly, the dynamic model of the linear rolling guide joint surface is established and its natural frequency is figured out. Then we use ANSYS to make finite element analysis of guide on whether the bolt joint is considered or not. Finally, the validity of finite element model is verified through modal test. By comparing the results of the two kinds of finite element analysis with the theoretical result, we can conclude that the finite element model considering the bolts joint is closer to the theoretical result. So the bolt joint has a great influence on the dynamic characteristics of linear rolling guide. This paper provides the theoretical guide for the research on the bolt joint.

Abstract: Aerodynamic drag reduction of commercial truck at high speed is one of the important ways to reduce its energy consumption. CFD simulation and wind tunnel tests are performed on a kind of commercial truck, to study the influence of the cab shape and different kinds of guide cowls on aerodynamic drag, and the impact mechanism was also analyzed. It shows that the cab shape will make great contributions to the aerodynamic drag while the truck travelling, and through improving the shape of cab, guiding the air flow passed, it can effectively reduce the aerodynamic drag and achieve energy saving.

Abstract: Automobile door closure’s sound quality is good or bad directly affecting customers evaluate to vehicle performance. Foreign automobile manufacturers spend lots of manpower, material and financial resources to improve and research door closure quality [1-3]. Door closure is important embodiment of product quality and performance, which is related to design method, manufacture process, sealing material, etc. This paper selects three different models and series cars, measuring their exterior door closure and anglicizing objective parameters of sound quality. It conclusion that front door frequency concentrated in 200-2000 Hz; back door’s concentrated in 315-2500Hz;The significant frequency band of characteristic loudness contains linear and A sound pressure level significant frequency band, etc.The result can provide ideas for automobile vibration and noise reduction.

Abstract: To test different car’s noise in a semi-anechoic room with different engine’s speed, measure and analysis engine noise’s characteristics and the dash panel’s sound insulation quantity. The conclusion is that：the engine noise gets bigger 10 dB(A) when engine speeds up every 1000 r/min; engine noise’s frequency mainly distributed in 1600 ~ 4000 Hz; peak part concentrates in the range 100 ~ 400 Hz; engine noise has no direct relation to engine’s displacement; cab noise frequency mainly concentrated in the range 250 ~ 630 Hz and the peaks exist in the intermediate and low frequency part, the high frequency part attenuates obviously which show the car’s dash panel has a good noise insulation and absorption effect in the high frequency part but not too ideal at the intermediate and low frequency especially in the range 250 ~ 630 Hz. These results have high practical value for the design of the automotive to decline noise and vibration.

Abstract: The principle and characteristic of odd-tooth sprocket and even-tooth sprocket of sintering machine were discussed from kinematics and dynamics. The advantages of the two types tooth shapes are given. The odd tooth can receive uniform force. The design of the odd tooth shape is determined by experience, it can’t accurately meet the movement needs. Even tooth sprocket tooth curve is derived from the analytical formula, but it receives non-uniform force. Both of the two types tooth shapes affect the sintering machine’s motion performance and thus affect the productivity and economy. The work helps to design the tooth shape of sintering machine.

Abstract: Through the bench test, the vibration characteristics of the front right support of the inline four-cylinder diesel engine is analyzed, and the MATLAB simulations and verifications are performed to the differential equation of 1 / 4 vibration model established by using the front right support as the research object. Experimental and simulation results show that the exciting force performs as basic frequency and second frequency and, the acceleration performs as basic frequency and low-frequency at low speed engine vibration; when it is in the high speed vibration, the exciting force is mainly manifested in the second frequency and the acceleration in high-frequency. The motion equation of 1/4 vibration model can reflect the status of the engine vibration well in the second frequency.