Applied Mechanics and Materials Vol. 160

Abstract: With the rapid development of the micro projector, the problems of its power consumption and heat dissipation have been increasingly serious. The thermal design can improve its reliability and cut costs at the design stage. This article selects DLP built-in micro projector provided by TI Company to analyze, uses thermal analysis software Flotherm to get the temperature distribution and temperature curves of the measuring points in the steady state, then compares the simulation results of the cooling optimization with the numerical analysis, which reduces the temperatures of thermal sources and shells. The conclusion supplies new theoretical basis on the development of mobile phones integrated with the projection function.

Abstract: The effects of tungsten doping on the oxygen-ion diffusion and the phase transition in La2Mo2–xWxO9 samples (x = 0.5, 0.75, 1.0, 1.2) were studied using internal friction method. The results show that two peaks were detected in the internal friction-temperature spectra in the La2Mo2-xWxO9 samples, the low-temperature relaxation peak is associated with oxygen ion diffusion, and the high-temperature peak is associated with a phase transition from the static disordered state to the dynamic disordered state of oxygen ion/vacancy distribution.

Abstract: Ferrate refers to the highest state of iron for + 6 price of the corresponding oxygen acid salt, the oxygen acid salt inherently a performance is very superior strong oxidizer, in modern economic society construction in the process of development, has a good application prospect. Based on the actual situation, with electrolytic method for high purity high iron potassium process as the research object, the high purity high iron potassium structural properties, preparation method, electrochemical method for high purity acid potassium high iron the influence factors of these four aspects to discuss how to use electrolytic method for high purity high iron potassium process more detailed analysis and explained, and then demonstrates the power needed to prepare high purity in high iron potassium process preparation is more superior than other ways of performance.

Abstract: Based on the strain energy density theory, the connotation of tangent modulus theory is developed. At critical equilibrium state, a dimensionless number Φ_t of a structure under pressure is introduced in this paper. Derived from the stress-strain curve of material, a four-parameter formula that contains Φ_t is established. This formula is referred to as the function of strength utilization ratio that may be used for calculating the inelastic buckling of deep submersible pressure hull.Φ_t can be used to express the effect of initial imperfection of the shell and to guide the experimental study. Compared with the data from some experiments or other methods, it has demonstrated that the method given by this paper is more precise and convenient for predicting the failure of thin and moderately thick shell under pressure.

Abstract: This paper proposes a novel multiscale slope feature extraction method using wavelet-based multiresolution anlaysis for gearboxes fault identification. The new method mainly includes the discrete wavelet transform (DWT), the variances calculation of multiscale detailed signals, and the wavelet-based multiscale slope features estimation. Experimental results show that the wavelet-based multiscale slope features show excellent clustering for different work conditions and have the merits of high accuracy and stability in classifying different conditions of gearbox.

Abstract: A discrete sliding mode control based on reaching law is investigated to suppress vibration of high-speed flexible manipulator. The finite element method and experimental modal test is applied to obtain the dynamic model of the system. Due to the influence from uncertain external disturbances and measurement noise, and uncertain parameters, sliding mode control has invariance of the sliding mode. The discrete sliding mode control approach with reaching law is applied to design the vibration controller which enables the system to be zero state as the system states are away from the equilibrium one due to external disturbances. The discrete Kalman filtering technique is employed to construct state estimator because the state variables cannot be directly measured. The first three natural frequencies and damping ratio are obtained by using experimental modal testing. The experimental control system is constructed and experimental validation is carried out using dSPACE real-time simulation system and MATLAB/Simulink. The experimental results showed that the proposed controller can effectively suppress the vibration response of the flexible manipulator.

Abstract: Fluid-solid coupling dynamic characteristics analysis of vertical cantilever lifting pipe in transporting coarse solid particles was conducted by adopting ADINA. Firstly, finite element models of pipe and fluid were built, which was solved by using ADINA/FSI module. Secondly dynamic characteristics of pipe vibration for different run-time, constrain conditions, volume concentration and transporting velocities were studied. Thirdly the stress and displacement characteristics were discussed under above conditions. The results were shown that stress and displacement will increase with transporting concentration and velocity rising; the shorter run-up time is, the bigger stress and displacement will be; stress and displacement of lifting pipe supportive anchor in weak constrain were greater than that in fixed connect condition. Analysis results have certain directive significance in future structure design, check, reducing vibration study for lifting pipeline in the ocean mining.

Abstract: According to the tangential force of crank pin approximately for radial force four times, between the radial gas force Fr and tangential gas force Ft acting on the orbiting scroll, the radial force is invariableness with the spindle rotation angle, but tangential force Ft with the spindle rotation angle changes, and in the discharge angle θ* at maximum. As a result of our comprehensive analyses to loads at crankshaft bearing of the scroll compressor as well as installation angle of the counter weight and mass of the counterweight, it is concluded that the imbalance residual quantity of the crank pin tangential force effects on crankshaft bearing and radial force acting on the crank pin, which results from gas force of orbiting scroll, is balanced, and the vibration of the scroll compressor is decreased. This paper puts forward a set of formulas, which are derived based on analysis of the loads at crankshaft of scroll compressor. The formulas can be used to determine the parameters of installation angle of the counterweight and the force of loads at crankshaft for scroll compressor.

Abstract: Eddy current sensor is widely used in engineering applications.When it was calibrated, generally used random error analysis method,but this will expand the range of measurement errors and limit its engineering applications.In this paper, we use a new error analysis method to analyze upper and lower limit of multiple batches measurement data. At the same time, catching up with a criterion for the measurement time. This can obtain the measurement accuracy more precise and have good practical value.