Applied Mechanics and Materials Vols. 34-35

Abstract: Because the web is not only the platform for information exchange but also the computational platform based on JavaScript engine, every computer having installed modern browser on the Internet can easily access the web and execute some JavaScript programs. Under above conditions, we develop a lightweight distributed computing system based on the web and JavaScript technologies. Our system plays an intermediary role between the IT expert who has to solve large-scale computational problem and end users on the Internet. In the other words, people could easily cooperate with each other to finish complicated computational problem through the support of our system.

Abstract: Reaction injection molding (RIM) is a rapid processing technique for the formation of polymer parts by direct polymerization in the mold. Polydicyclopentadiene (PDCPD)/Clay nanocomposites with various amounts of clay were synthesized with a Gusmer-Decker machine by RIM, and the specific injection conditions of the nanocomposites were obtained. The results of X-ray diffraction (XRD) diagrams of the nanocomposites showed that clay were completely exfoliated. The tribological behaviors of PDCPD nanocomposites were studied using an MM-200 friction and wear tester. The experimental results showed that the wear mass loss of nanocomposites reach the minimum while the MMT content of the nanocomposites is 1wt%. The values of friction coefficient almost keep constant within the range of MMT content as added.The worn surface of PDCPD nanocomposites was examined with a scanning electron microscope (SEM) and the friction and wear mechanism was discussed.

Abstract: Drive axle assembly is one of the key components of automotive, and the design quality of drive axle assembly can affect the driving performance, fuel consumption and serve life of vehicle greatly, therefore it is very important to adopt optimization to design the final drive and planetary transmission of vehicle. To reduce size and weight of transmission, the objective function should be specified that the sum of volume of pitch cylinder of sun gear and planet gears in planetary transmission incline to minimum. The objective function with penalty terms is built by penalty strategy with addition type, so as to transform the constrained optimization into the unconstrained optimization.Then the simulated annealing algorithm based on penalty strategy is adopted to solver the optimization model.

Abstract: A combination of fractional Fourier transform (FRFT) and time-frequency method is presented to identify ambient excited modes. In this method, Gabor expansion is applied to identify natural frequencies and damping ratios. The signal autocorrelation can enhance energy distribution of each channel signal, which can help to identify parameter. FRFT is a good tool to estimate excitation signal. A simulation example is presented to demonstrate the performance of this method. The results have shown that the proposed method gives a reasonable estimation of modal parameters and excitation signal from response signals.

Abstract: Multiple criteria decision making(MCDM) is widely used in selection from a set of available alternatives with multiple criteria, approaches to which includes fuzzy comprehensive evaluation(FCE), grey relational analysis(GRA), and technique for order preference by similarity to ideal solution(TOPSIS), and so on. First analyzes the limitations of various methods: only considering the overall effect of attribute indicators in the method of FCE, only considering the shape similarity of data curve between comparative scheme and ideal solution in GRA and only considering position approximation in TOPSIS. Second proposes a new method of comprehensive evaluation which takes into account both shape similarity and position approximation. The validity of this method has been further proved by an example of suppliers selection.

Abstract: In this paper, the variable speed grinding experiments at high speed have been studied systematically, and the method of improving the surface quality of high-speed grinding has been discussed on the basis of analysis of the chatter and the stability of the high-speed grinder. Through the variable speed grinding experiments at high speed, the vibration characteristics were measured by the vibration energy, and the power spectrum were analyzed by the maximum entropy spectral estimation of the vibration signals in time series. The results confirm that the chatter of high-speed grinding can be suppressed by the variable speed grinding to a certain extent.

Abstract: This paper presents a novel compliant linear guided mechanism (CLGM) to replace traditional spring and translation joint to transfer motion and force with its advanced guiding characteristics. In view of the incompatible relationship between axial stiffness and transverse stiffness of CLGM, eight kinds of CLGMs were developed by using building block approach based on fixed-guided flexure beam. The finite element analysis (FEA) models of eight CLGMs were built to complete numerical analysis on the force-displacement in axis and off-axis direction with same geometric sizes. The FEA results show that the structure configuration of Type 2-Type 8 can achieve a larger axial travel, Type 2 and Type4 have the advanced guiding characteristic with higher ratio of axial/transverse stiffness. Analysis indicates that the building block approach is an efficient method to complete the conceptual synthesis of compliant mechanism and FEA is effective on the structure optimization for the required compliance and stiffness in axial and transverse direction.

Abstract: A turbocharger is fitted to a diesel in order to enhance the inlet charge pressure, hence increasing the fresh air in the cylinder, then more fuel can be injected into the cylinder and sequentially more engine power can put out. The electrical aided turbocharged system is a mechanism adding a high speed electronic motor into a turbocharger shaft. The electronic motor can work as a motor to drive the turbocharger shaft and as a generator to generate electricity energy to storage energy. According to certain constraint conditions, the controlling strategy of the hybrid turbocharged system is presented. The simulation results about key work points reveal that controlling the turbocharged engine following the strategy can enhance the engine performance.

Abstract: Gaussian processes (GP) is a machine learning method which has become a power tool for solving highly nonlinear problems. Aiming to the fact that it is still difficult to reasonably determine the fuel consumption per 100km for automobile engine，the model based on GP machine learning was proposed for prediction the fuel consumption per 100km for automobile engine. According to few training samples，the nonlinear mapping relationship between the fuel consumption per 100km and its influencing factors was established by GP machine learning model. The model was applied to a real engineering. The results of study showed that GP machine learning model is feasible, effective and simple to implement for prediction the fuel consumption. It has the merits of self - adaptive parameters determination and excellent capacity for solving nonlinear small samples problems.

Abstract: To control the tension dynamic behaviors of heavy scraper conveyor self-adjusting system used for the chain initial tension of the scraper conveyor was considered. Hydraulic control system according to the principle was designed and the control theory of the system was established. the new fuzzy- PID controller used to the self-adjusting system was designed to limit the minimum tension point to some given scope. the example of simulation proved that the increase of power loss due to the higher tension and the chain escaping from sprocket wheel due to the lower tension can be avoided.