Applied Mechanics and Materials Vols. 48-49

Abstract: The Properties of natural shear strength for municipal solid waste are studied by applying a new developed direct shear testing instrument. The municipal solid waste is divided into three parts: incompressible solid waste, reinforced material that is difficult to be biodegraded and the material that is easy to be biodegraded. The properties of these three parts are 15%, 5% and 80%, respectively. A series of laboratory tests have been conducted for different initial void ratio, and different pressure applied on the test specimen. The testing results show that the initial void ratio is a key factor for the natural shear strength of the municipal solid waste, the relationship between the shear stress and the shear strain is a strain hardening curve, the shear stress gradually increases with the shear strain. Besides, the natural shear strength shows a linear relationship to the pressure applied on the test specimen, and it is in accordance with the law of coulomb. According to the fitted lines, the shear strength parameters are obtained. The cohesion varies from 4.7 to 12.6kPa, and the internal friction angle varies from 14.5 to 18.3 degree for the shear strain is equal to 5%. When the shear strain is equal to 20%, the cohesion varies from 8.5 to 17.2kPa, and the internal friction angle varies from 25.5 to 30.7 degree.

Abstract: By using shore hardness test method, the effects of adhesion strength, coating thickness, basic material, and hammer on the restitution coefficient are studied experimentally and theoretically. The results show that the restitution coefficient increases with the curvature radius of the hammer indenter. In the same condition, the larger the restitution coefficient, the stronger the adhesion strength, while the smaller the restitution coefficient, and the weaker the adhesion strength.

Abstract: The sky luminance distribution model studied by information methods use a new arithmetic to solve complex optimization heuristic algorithm, ant colony system. Through analyzing and optimizing the effect factors of sky luminance by the ant colony system, the study got the coefficients value of sky relative luminance distribution numerical expressions. Based on the study, develop a set of convenient and practical sky luminance model calculation software, which can provide an intuitive and easy calculation. This model has higher precision. It provides valuable results for day lighting using, especially high precise and standard work of day lighting design both in theory and application.

Abstract: This paper established a neural network based on Bayesian regularization, which was used for temperature prediction of feature points in friction stir welding metal. Sample data included rotation speed, welding speed, distance, depth, time and temperature of feature points. The representative sample data was obtained through the orthogonal experiments. Neural network was improved by Bayesian algorithm, and the constraint term representing complexity of network was introduced into the objective function. Then generalization ability of neural networks has been enhanced. Prediction accuracy, training time and stability of network are better than in the traditional neural network. Test proved that this smaller network model operates faster, and it can accurately predict the temperature of feature points of friction stir welding.

Abstract: The aspect ratio is one of the important factors that impact the corrugated box compression strength. In this paper, the three most commonly method that can be used to obtain the corrugated boxes’ compression strength, namely testing method, classic formula method and computer simulation method were compared. Selecting some 0201 BC flute corrugated boxes as the object, on the condition that the cardboard materials, carton height and circumference of the corrugated box is at the same, the compression strength of corrugated boxes which aspect range from 1 to 3 were tested and calculated respectively by compression strength testing method and classical formula. The results show that when the aspect ratio changes from 1 to 3, the compression strength increase at first, and then decrease; the compression strength reach maximum when the aspect ratio at 1.6 or so. The results show that the classic formula calculation data are large deviate from the testing ones. Research shows that due to not fully take into account the influence of corrugated cardboard quality, box forming process, temperature and humidity and other factors, the currently classic compression strength formula are more conservative.

Abstract: The conjugating cam beating-up mechanism is the key parts of looms, and it is one reason which determines the speed and steady state of motion. The paper uses ADAMS to build the model of it and makes kinematics simulation and dynamics simulation.

Abstract: The optimized model of machine tool processing is a typical one of constrained optimized model. This paper investigates the construction of optimized model of milling under a variety of objective or subjective environment, and aims at minimizing the cost and maximizing the profits.

Abstract: In this paper, the charge-pump PLL structure is well analyzed. By using top-down method, the digital PLL is designed from frequency phase detector, charge pump, loop filter, VCO to frequency divider. Based on 0.5μm CMOS mixed signal process, the schematic and layout design is finished on Cadence IC 5.1.4.1, and Hspice is used for the simulation. The layout verification and parasitic extraction is completed on industry mainstream Calibre software. Simulation results show that the digital PLL is with a 100MHz center frequency, the locking range is between 20MHz~60MHz, the locking time is less than 1.5μs, and phase noise is -105dBc/Hz. The design has implemented the digital signal lock function and it can be used as an IP hard core in the clock recovery of communication systems and frequency synthesis of digital systems.

Abstract: The discrete wavelet transform based on the orthogonal wavelet bases has the disadvantage of shift-variant. In this paper, using the compactly supported dyadic orthogonal real-valued wavelet bases to construct the compactly supported dyadic orthogonal linear phase complex wavelet (LCW) bases in terms of alternately lifting scheme. Linear phase complex wavelet can separate the envelope of the flicker signal. The core of the method is a pair of Hilbert transform including the flicker signal in wavelet field is come into being, i.e. a pair of quadrature components with the same amplitude and the same frequency can be used to realize the demodulation of an amplitude modulated voltage flicker signal. Simulation experiments show the method proposed has the characteristic of shift-invariant comparing with the traditional discrete wavelet transform, result of separating envelope of the flicker signal is independent of initial time recording signal.

Abstract: By theoretical analysis and laboratory test, the model parameters of Duncan-Chang for municipal solid waste have been studied. To obtain the mechanical parameters, a new simple and practical method has been established. Research results show that the damage ratio is 0.6, parameter n is about 1.05, parameter F varies between 0 and 0.1, and parameter G varies between 0.3 and 0.4. Besides, the relationship between parameter k and the initial void ratio is linear, and the slope of the line is 5.0.