Applied Mechanics and Materials Vol. 164

Abstract: In this paper, a nonlinear gyroscopic system is investigated. Two sufficient conditions to ensure the existence of oscillations for the system are proposed. Simulations are demonstrated for the provided results. In the study, the authors has researched the nonlinear gyroscopic system from the mechanics perspective, which will be useful in dynamic mechanical system, especially for parametric vibration. In fact, the nonlinear gyroscopic system is closely connected with mechanics, and they also influences each other during study.

Abstract: This paper describes a method about hydraulic cylinder cold pulling processing. Take seamless steel tubes as raw materials, they are acidified and phosphates before the cold pulling to guarantee that mold and pipe have a good lubrication and have a high temperature stability during the cold pulling processing, thus the cold pulling process can be stable . When the seamless steel tubes are brought into the drawing processing, a process provides with a Hydraulic pulling machine, matches special cold pulling die, then they occur plastic deformation uniformly and satisfy the dimension requirements ,whose accuracy can reach IT7~IT8 and the surface roughness is Ra0.4 ~ 0.6. At the same time, it causes producing cold hardening, which makes the material strengthened. Compared with the traditional processing methods, drawing processing can remarkably improve the production efficiency, ensure product quality and improve the qualification rate of finished products.

Abstract: On the basis of the energy conservation and the state equation of the ideal gas, a formula of quasi-static pressures of the confined explosions calculating was derived under the constant entropy assumption of the detonation products expansion and the constant volume assumption of the chemical reactions. Taking the TNT explosive as an example, the quasi-static pressures of the confined explosion either considering the influence of the chemical reactions or not were calculated and the quasi-static pressures of the confined space were obtained

Abstract: To determine the failure cause of rolling bearing of a factory heating device, oil samples extracted from the recovery of lubricant oil and were tested by comprehensive oil monitoring techniques (including physico-chemical properties analysis, pollution degree detection and ferrography wear particle analysis). The results show that root cause of failure is the operating temperature of the bearing is too high. Failure form is burning. Therefore, the application of oil monitoring techniques to analyze the mechanical failure mechanism, to prevent mechanical failure and extend machine life is very helpful.

Abstract: Thermal learn calculation was used on the process of glass melting of alkali-free glass, the relationship type between free enthalpy and temperature was obtained. Results show that B2O3 begin to melt at T=700 K, this reaction contained more step reactions. Carbonate barium (BaCO3) decomposed to generated BaO and CO2 around 1300 K, BaO began reaction with small amounts SiO2 to generate silicate. BaO and SiO2 were easy to react in low temperature because of their high reactivity. Reaction between SiO2 and Al2O3 was a reversible reactions, the turning point was T=1700 K. Combined with the calculation results, each reaction in different temperature range was discussed. In addition, the mechanism of reaction in the glass melting process was studied and discussed by use of thermogravimetric-differential scanning calorimetry.

Abstract: Magnetic fluid based liquid mirrors represent a promising technology. Compared with the conventional solid mirrors, magnetic fluid deformable mirrors (MFDMs) have the advantages of large strokes, low cost and easy scalability. In this paper, the brief history of the development of MFDMs was first introduced, the working principle of MFDMs with fluid mechanics and electromagnetic field was presented next and then the advantages of MFDMs as well as their challenges are discussed.

Abstract: Commonly used finite element strength reduction to calculate the safety factor of slope，to analyze the stability of the slope[1～3]. Recently it also proposed the methods to evaluate the safety factor for the stability of surrounding rock of underground chambers and supporting structural mechanics[4～6]. For Qinling Mountains of the complex geological conditions in the Maanziliang highway tunnel, this article use the finite element method from the bolt resist tension, bolt length, the force of sprayed layer of concrete to computing gradeⅤsurrounding rock section of primary support safety factor, to give evaluation to support mechanics of the Maanziliang tunnel.

Abstract: The electro-hydraulic position-servo synchronization system of horizontal pipes connector was designed in order to connect two pipes in deep sea and make sure the journey of synchronization hydro-cylinders in the hydraulic system is less than 2 mm.Its transfer function of symmetric servo controlling oil-cylinder electro-hydraulic servo system were derived . Simulation analysis of its dynamic characteristic was done, and PID controller was applied on the system to regulate two hydraulic cylinder synchronization controls. In the end ,when the proportionality coefficient is Kp=0.55,integral coefficient is Ki=60,differential coefficient is Kd=0,the error of synchronic displacement was less than 0.5 mm, that achieved the request of the control system.

Abstract: TC4 blades are one of the major parts of the aero engine, and the examples of engine invalid and even wrecked are common. In this paper, a 3D analysis system of the vibration behaviors of the TC4 blades is given. The 3D analysis model of blade was described using 20 nodes elements. The finite element procedure was worked out using the blade vibration behaviors analysis of the aero engine. At last, the modal shapes and stress nephograms of the first six frequencies are gotten which influenced the blade vibration characteristics. Results show that the program has offered an effective, flexible research means for analyzing dynamic response of TC4 blades.

Abstract: One of the important methods for studying the valve train system is simulation. So the feasibility of valve motion simulation by Pro/E is discussed in this paper. After model establishing and connection completing, the valve motion is simulated and some results are reached. It can be seen from the results that valve motion can be simulated based on Pro/E environment. It also be seen that the valve acceleration varied at high frequency and the impact between the valve and seat is existed for the studied valve system. For studied valve it meets the demand of the engine