Applied Mechanics and Materials Vols. 34-35

Abstract: Flow and pressure regulation axial piston pump is studied in this paper. Model of the pump is built in AMESIm, and then characteristics of flow rate and pressure are calculated and analyzed in this model. This provides a good platform to the design and research of axial piston pump.

Abstract: Product design is a problem-solving activity based on knowledge. This paper is devoted to presenting a systematic knowledge representation method of principle solution based on semantic network model. For the expression of product knowledge, the semantic object, constraints and their relationships among the expression of the semantic object network model are proposed step by step. Then the principle solution representation model based on semantic network model is put forwards. The knowledge representation of a car is given as an example, which demonstrates that this method is obviously helpful for knowledge-based design system and product innovation.

Abstract: In the milling process of thin wall workpiece, the more cutter flutes, the high metal remove ratio can be gotten. Milling forces with two-futes and four-flutes milling cutter were anlysised and compared using finite element method. The possibility and advantage of machining thin wall workpiece with four flutes milling cutter was introduced. The four flutes cutter can improve the metal remove ratio, and cutting force is more uniform in general.

Abstract: The plasma sprayed gradated coating with the bottom layer of NiCrAlY and the top layer of (ZrO2+CaO) was prepared on the 1Cr18Ni9Ti steel surface by the plasma spraying technique. The phase structure and morphology of the gradated coating were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The high temperature oxidation resistance of the plasma sprayed samples at 800°C was investigated. The oxidation kinetics curve was worked out. The wear-resistance behavior of the graduated coating under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results show that the thickness of gradated coating is about 320μm. The plasma sprayed gradated coating on stainless steel surface can improve the high temperature oxidation resistance of stainless steel. The oxidation rate of stainless steel is less than that of plasma sprayed gradated coating. The oxidation coating of plasma sprayed sample was very dense and is not easily exfoliated. The dense oxidation coating prevents the stainless steel from more oxidation. The friction coefficient of the 1Cr18Ni9Ti substrate was about 0.33 on dry sliding against the GCr15 steel, while the graduated coating experienced abated friction coefficient to 0.21 on the same testing condition.

Abstract: To study the flywheel storage energy in enhancing the construction machinery engine speed stability, Dynamic model on engine and engine connecting another flywheel is established. With a group of experiment data, load changing effecting the engine speed is compared when the storage energy flywheel is assembled and not. The results indicate that high frequency engine speed fluctuating is less when the storage energy flywheel is assembled, the drive and economy performance is better, and added energy loss is only for friction.

Abstract: In order to offer theoretical basis for the vibration prevention and noise reduction for the area along urban rail traffic line, the propagation laws of environmental vibration are summarized by analyzing observation data in time and frequency domain based on actual field observation data in Beijing. The mathematical statistics method under the criterion of least-squares has been used to study the vibration propagation and to establish the empirical formula of vertical ground vibration. The results obtained from the empirical formulas proposed agree with the results of field observation well. The vertical ground vibration level is much higher than that of horizontal. So the vertical ground vibration level is the most important aspect when evaluating ground environmental vibration level. The field response near the rail depends on the high frequency vibration caused by moving train and that far from the rail is dominated by the natural vibration frequency of train and the field vibration. The response amplitude of environmental vibration would be changed when load changed.

Abstract: Four models of the tunnel bedding structure were analyzed under the impact loads of the train by simulating the infrastructure under the track. In this study, we examined the relationship between the vertical dynamic coefficient and the train velocity, and also analyzed the damage sustained by the bedding structure under the static and dynamic loads. It is suggested that the damage in the concrete bedding is detected in the longitudinal direction, immediately below the two rails, and that this damage is likely to occur not from attaining an elastic limit under static loads but more likely from damage accumulation in fatigue due to repeated loadings. It is not advisable to improve the tunnel bedding structure by simply increasing the thickness of the concrete bedding board; however, the bending resistance of the tunnel bedding structure can be enhanced by adopting compact reinforced concrete structure.

Abstract: In order to reveal the relation between concrete strength grade and concrete permeability, based on C20, C25, C30 and C40 concrete impermeability and gas-proof tests, the effects of concrete strength grade on concrete impermeability and gas-proof are investigated. The results show that the gas-proof and impermeability property of concrete increase when concrete strength grade are subjected to higher one.

Abstract: This paper focuses on the research of the de-noising of the passive sonar based on the Gabor. Based on the modeling and simulating of the underwater robot about ship radiated noise, this paper analyzes and compares the effect of de-noising of the passive sonar of ship radiated noise. It is shown that better de-noising effect are achieved by using the Gabor method. This method have a significant foreground in de-noising of passive sonar.

Abstract: With the intention of researching suspension’s effect on the self-excited vibration of tire, according to the characters of polygonal wear, the twist beam suspension of car PassatB5 was simplified to proper mechanical model in the method of FEA. Then, making the coupling of lateral friction self-excited vibration of tire and draw-wrest operation of lengthways pendulum arm taking the previously built friction coefficient model into account which could cause the self-excited vibration of tire, besides the velocity of car’s driving, another exciting source could be found in this model.