Applied Mechanics and Materials Vol. 487

Abstract: A duct with varying cross-sections can show some essential features of the motion of foam in porous media. In this paper, the effective viscosity of the bubbles train moving through cylindrical ducts with sinusoidal cross-section was experimentally measured. The test tube has total length of 1.14 m and has constrictions at interval of 0.0095 m. It is found that the foam effective viscosity is much higher than water viscosity and it is possible to extend the foam rheology correlations in constant cross section ducts to predict the flow differences in waving ducts.

Abstract: Considering the damping and stiffness for mechanical system of laser heat assisted variable cross-section roll forming machine, in order to obtain the angular acceleration and angular velocity of servo motor and ball screw, the kinetic equation of the system is established using the Lagrange's equations. The results are great significance in depth study and optimization of dynamics of mechanical systems.

Abstract: The spindle of a 10 kw vertical axis wind turbine is designed in this paper, and the relevant geometric parameters is given, and build the geometry of the finite element model. Calculation of the spindle under wind load and dead weight , and analyse the spindle Von Mess stress, deformation nephogram, and give the former six order vibration mode of the spindle. Through the analysis, Then the design parameters of the spindle are optimized. and the optimized structure of spindle has been got. optimized spindle is in lower quality, more satisfy the requirement of wind turbine running under high load at the same time .

Abstract: Charge amplifier is the key component in the pre-processing circuit of the sensors. With the development of the sensor technology, the charge amplifier on the market has not been able to meet the requirement of the actual measurement. In this paper, a LF356-based charge amplifier is suitable for the conversion circuit of the polyvinylidene fluoride (PVDF) piezoelectric sensor, duing to its small volume, low power consumption and strong anti-interference. The fesibility and reliability of the charge amplifier are verified by simulating the circuit with Multisim10 and testing the hardware circuit. This charge amplifier achieves a volume of 19.32 cm³ and a bandwidth between 20kHz and 150kHz at a power consumption of 1 mW. Performance of this charge amplifier is investigated when it is connected to a standrad signal source, achieving a gain of 10 times.

Abstract: A tube with varying cross sections can capture some essential features of the motion of foam in porous media. In this paper, experiments were carried out concerning a moving bubbles train through cylindrical ducts with sinusoidal cross-section. The test tube has total length of 1.14 m and has constrictions at interval of 0.0095 m. The visual images of a single lamella motion were recorded and were interpreted. It is found the lamella decelerates in the diverging portion while accelerates in the converging part of the tube.

Abstract: In this paper, we present an acoustic-structure couple interaction model of partial discharge (PD) in Gas Insulated Switchgear, the interaction between the internal acoustic source of partial discharge and structure of GIS is simulated with the finite element analysis, and the internal and external acoustic pressure levels distribution of GIS is obtained. The results based on the frequency sweep shown that the internal acoustic pressure levels is bigger than the external acoustic pressure levels of GIS in the ultrasonic frequency spectrum,it suggests that it should use the ultrasonic sensor with a broadband spectrum response to measure partial discharge in GIS, which can obtain high sensitivity. In addition, the external sound pressure of GIS is very small, and the signal of the Ultrasonic sensors must be amplified for measurement. Meanwhile, the outside acoustic pressure of the epoxy insulator is so small that it can properly judge the adjacent GIS unit partial discharge conditions.

Abstract: Finite element analysis has been done to analyze pump bearing assembly in interference assembly condition by ANSYS software. The press-in assembly environment has been simulated, and the maximum stress and maximum deformation of inner race have been analyzed. Studies show that with the increase of bearing size, the change law of maximum stress and maximum deformation does not single unidirectionally increase or decrease simply. At the same time, the interference value also influences the change law. So, in the bearing assembly tolerance selection the influence of the interference must be considered fully. The finite element analysis can guide the selection of fit tolerance.

Abstract: In order to save space mission cost, prolonging the working life of the spacecraft and improving the flexibility and capable of performing various tasks should get more attention on orbit servicing technology. For the docking process of a new type of two independent service in-orbit spacecraft, this paper finished the kinematics analysis, for the whole docking capture process, two groups of different initial conditions and control function of the simulation analysis were finished by the ADAMS software. The results prove that the docking mechanism performance is very good, and reliable connection can be realized in the general initial conditions.

Abstract: Reinforced concrete eccentric compression member is one of the most common structural member. Eccentric compression members are divided into large eccentric compression members and small eccentric compression members. Uncertainty of calculation, geometric size and concrete strength were considered as random variables, the reliability of eccentric compression members were discussed by monte carlo simulation.

Abstract: The study is to employ the analysis method of CFD simulation, when putting the insertion flow sensor in large-diameter pipe, to analyse the characteristics of flow field distribution of the insertion flow sensor in detail. It reveals the flow field distribution at the position of average flowrate and the vortex shedding around insertion flow sensor, which provides an important basis for design of the insertion flow sensor with high performance.