Advanced Materials Research Vols. 228-229

Abstract: Virtual Assembly (VA) is an advanced tool for assembly design. Current VA system lacks of intelligent decision support especially in assignment of assembly planning task. There are already some research to enhance the perception ability and intelligent support of VR. However, most of them are focusing on the auto mating or moving navigation, while the study on assembly task is few. The paper analyzed the task in virtual assembly and discussed the system level task as a main topic, which indicated that ‘work-flow’ was a suitably way to implement task aware. Therefore a BDI agent model for assembly task was proposed on the bases of work-flow and the architecture of it was given. After these, the reasoning mechanism was designed to support assembly task awareness.

Abstract: In order to investigate the influence of fretting induced by a shrink-fit shaft and hub subjected to rotating bending on crack propagation on different position, small specimens consisted of shaft and hub were tested on the four point rotating bending fatigue test machine. The experimental result shows that the fretting fatigue life of specimen with notch outside the shaft-hub contact is shortest, and the fretting fatigue life of specimen with notch inside the shaft-hub contact is longest.

Abstract: This paper proposes to verify and test the vibration of diesel’s undercarriage got by virtual measure and actual measure through the analysis of time domain characteristics and amplitude frequency response characteristics of three-orientation vibrant speed of diesel’s undercarriage, represents the difference in time domain characteristics and amplitude frequency response characteristics got by virtual measure and actual measure, expounds the reasons of difference and puts forward a method to diminution the difference. It proves that virtual measure can replace actual measure in a way, though there are some difference in existence, we can erase these difference to the best of ours’ abilities through enough analysis.

Abstract: The effect of adding polypropylene fibers; with different shapes and volume fractions; on the compressive strength, modulus of rupture, load-deflection curve and flexural toughness (equivalent flexural strength ratio) of concrete was investigated. Crimped and twisted polypropylene fibers were used with 0.0%, 0.2%, 0.4% and 0.6% volume fractions. It was found that the compressive strength, flexural strength and the equivalent flexural strength ratio of concrete increased about 11%, 25% and 40% respectively by adding 0.6% volume fraction of twisted polypropylene fiber. In addition; it was found that the contribution of polypropylene fiber to the flexural strength and flexural toughness was more effective when twisted polypropylene fiber was added comparing to crimped polypropylene fibers. The experimental results were used in numerical example using FAARFIELD program to explore the airfield pavement thickness reduction resulted from polypropylene fiber incorporation.

Abstract: The effect of varying the TiO2–content on the lead-free high refractive index glass based on 25 wt% barium carbonate added in replacing lead oxide was prepared and its physical, optical, and electrical properties were investigated. Seven glass samples were synthesized and characterized by using an analytical balance, a refractometer, a LCR meter and an X-ray diffractometer. Specific gravity, refractive index, and dielectric constant increased linearly as the increasing of the TiO2-content. The amorphous state of modification of glass structure due to TiO2 addition was confirmed.

Abstract: The nano-antimony particles with different shape, size and stability are prepared by electrochemical method under the dilute hydrochloric acid electrolyte including the surface dispersant OP-10 and different current densities. The influences of current density on the shape and size of nanometer antimony particles prepared by electrochemical method are analyzed by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The results show that nano-antimony powder can be prepared by electrochemical method, and the antimony powder possesses the crystal structure with orthorhombic hexahedron. The current density has a significant impact on the agglomeration, shape and size of antimony powder. The size and shape of antimony powder are determined by the nucleation rate of nano-antimony and combination capacity of antimony ions and OP-10 surface dispersing agents affected by current density. When the current density is 25mA/cm2, the average particle size is 12nm or so, the shape is spherical, and the nano-antimony particles are well dispersed and no agglomeration.

Abstract: Hexagonal W-type ferrite BaZn0.6Co1.4Fe16O27 was prepared by the method of coprecipitation with flux. The formation, microstructure, element composition and phases were analyzed by TG-DTA, SEM, EDS and XRD. The micrograph showed that the ferrite grains appeared to be hexagonal schistose texture obviously and the dimension of the grains was about 10μm. The product powders were composed mainly of BaZn0.6Co1.4Fe16O27 and few other phases such as α-Fe2O3, M-type ferrite (BaFe12O19) and S-type ferrite (MeFe2O4, Me for Zn or Co) were also found in the product. Electromagnetic parameters and microwave absorption capability were measured by the microwave vector network analyzer. The results showed that the reflection loss (RL) of the sample came up to -10dB in the spectrum from 8GHz to 18GHz and -20dB in the spectrum from 9.5GHz to 16GHz.

Abstract: To solve the thermal deformation caused by thermal load of heavy machinery gearbox, it is established that coupled analysis model to carry out the analysis on box structure's thermal characteristic by using the finite element thermal structure coupled analysis. The model figures out the steady-state temperature distribution of the box, the results will be the boundary condition for box thermal structural coupled analysis. It is calculated which stress distribution and displacement cloud pictures of the box under the interaction of thermal and structural load. The results show that deformation of the heavy machinery gearbox is cased by structural loads and thermal loads. And the thermal load is an important factor that controls box deformation to ensure the accuracy and reliability of heavy gear transmission, which can not be ignored.

Abstract: Bi2Sr2Co2-xCuxOy (x=0.0, 0.2, 0.4) samples were prepared by solid-state reaction method and the effect of Cu substitution on the high-temperature thermoelectric properties was investigated. The presence of Cu element improved the grain size and the thermoelectric properties increased owing to the simultaneous increase of conductivity and Seebeck coefficients. The optimal thermoelectric performance was obtained in x=0.2 sample and the power factor was two times as large as that in Cu-free sample at 923K.

Abstract: A relatively new process called microarc oxidation (MAO), also called plasma electrolytic oxidation (PEO), has emerged as a unique technique to produce hard, thick ceramic oxide coatings on different Mg or Al alloys. The magnesium offers various possibilities of application in industry, but its poor property in corrosion resistance, wear resistance, hardness and so on, limited its application. Through microarc oxidation, ceramic coating is directly formed on the surface of pure magnesium, by which its surface property is greatly improved. In this paper, a dense ceramic oxide ceramic coating was prepared on the magnesium by microarc oxidation in a Na2SiO3-Na2WO4-KOH-Na2EDTA electrolytic solution. The surface morphology of the coating was observed by the Scanning Electron Microscope (SEM). Using the X-ray diffraction (XRD), the phase structure of the coating was analyzed. The friction and wear behavior of the micro-arc oxidation ceramic coating under dry sliding against GCr15 steel was evaluated on a ball-on-disc test rig. The results showed that the magnesium was characterized by adhesion wear and scuffing under dry sliding against the steel, while the surface micro-arc oxidation ceramic coating experienced much abated adhesion wear and scuffing under the same testing condition. The micro-arc oxidation ceramic coating showed good friction-reducing and fair antiwear ability in dry sliding against the steel.