Applied Mechanics and Materials Vol. 757

Abstract: The phase equilibria in the Fe-Nb-V ternary system were investigated by means of optical microscopy, electron probe microanalysis. One isothermal section in the Fe-Nb-V ternary system at 1050 °C was firstly experimentally established. Present experimental results indicate that: (1) there is a large (Nb, V) continuous bcc solid solution; (2) there are the larger solubilities of V in the FeNb and Fe₂Nb phases. The newly determined phase equilibria in this system will provide important support for the development of microalloyed steels.

Abstract: Boron nitride/ethylene alcohol (BN/EG) nanofluid was synthesized by two-step method. The effect of dispersant on stability, viscosity and thermal conductivity enhancement was investigated. The experimental results indicated that the addition of anionic dispersant (SHMP) and catioic dispersant (CTAB) will induce the severe deterioration of stability of BN/EG nanofluids. PVP, which belonging to non-ionic dispersant, can improve the stability and fluidity obviously besides keeping the enhancement of thermal conductivity.

Abstract: In this paper, the three-dimensional motion of two bubbles in melt Aluminum was simulated by using level set method. Through changing the positions and sizes of two bubbles, the influence of bubbles wake flow and their interaction are considered. Our numerical simulations demonstrate the bubbles characteristic behavior such as distortion, attraction, and repulsion. The velocity field around the bubbles reveals the interaction between the wakes of two bubbles in fluid dynamics. For the two bubbles placed horizontally or vertically, it is found that the coalescence of bubbles may happen when 50% of the below bubble’s projected area enters the wake zone of the upper bubble.

Abstract: The inclusion complex of β-cyclodextrin (β-CD) and dibutyl phosphite (T304) was prepared by trituration. The tribological properties of the complex with different concentrations were investigated by a four-ball tester in the solution of polyethylene glycol-600 (PEG-600). The tribological test results showed that the complex exhibited better anti-friction and anti-wear properties than β-CD under different loads, and it was noted that the tribo-system showed the least friction coefficient when the concentration of the complex was 0.9%. It was proposed that the complex was decomposed into various molecular fragments and the T304 molecules were released under the friction condition. The XPS analytical results on the worn surfaces revealed that phosphide film formed by the released T304 played a major role and the iron alkoxide and carbon deposition films formed by the β-CD fragments had better anti-friction effect on the phosphide film surface. The interactions of different films resulted in the formation of a mixed boundary lubrication film.

Abstract: Three models including scheme A, B and C of the semicircular or crescent surface cracks, and two ones including scheme D and E of elliptical inner cracks in the vessel wall in three-dimensional are estabished with ABAQUS software. The values of the crack tip of the stress intensity factor are calculated and compared with the empirical results based on BS 7910 standard. The results show that scheme C and D are better, which provide a new method for the modeling and simulation of three-dimensional components containing cracks with finite element method.

Abstract: A numerical investigate of unsteady (rotor 37) based on dual time step is carried out .Results were used to identify the existence of an interface between the approach fluid and the tip-leakage flow. This paper discusses mechanism of spike stall.

Abstract: High pressure gas cylinder thread joint is the weak link in high pressure gas cylinders, The cylinders in use and the operating process, the main causes of cylinder screw thread failure is the improper preload. In this paper, cylindrical high-pressure cylinders threaded,connection for example,according to the bottleneck and the bottlevalve for high pressure gas cylinder structure, material and mechanical characteristics, establishing 3D solid model of the high-pressure cylinders connected by using the finite element software ANSYS, 3D model is applied to high pressure cylinders, thread connection analysis.

Abstract: Finite element model of dynamic tuned gyroscope (DTG) was founded using finite element software of ANSYS. Natural frequencies and vibration modalities of DTG in cases of both being static and rotating were studied respectively through the method of modal analysis, and also various vibration modalities influence on output of gyroscope was analyzed.

Abstract: The gas cylinder is used in most cases, which is often made from alloy structural steel. When it is used in high pressure gas cylinder, the larger volume, higher weight, and larger length will produce. It is found that both in theoretical and experimental analysis that this kind of material has syntactical mechanical properties such as the tension strength and plastic strength, so it can be reused many times.