Advanced Materials Research Vols. 652-654

Abstract: Reliability of eccentric wear casing was studied by Monte-Carlo and finite element method. In different internal pressures, calculated reliability of P110 steel grade 9 ⁵/₈ inches casing with wear depth less than 0.5 times wall thickness. The influence of different cement ring circumferential missing amount and stratum pressures on wear casing reliability were presented. The results provide basis for casing safety evaluation and reasonable replacement.

Abstract: We usually calculate the fatigue damage by superimposed respective injury; the paper brings up the superimposed load spectrum method considering load sequence. It superimposed on the load spectrum of each load and obtained the total damage of total stress time history. Finally, as an example, bolster’s damage is calculated by two ways. By contrast, the damage is larger by former method. The injury results based on the method of superimposed load spectrum is closer to the actual situation. Therefore, the research method presented in this paper can provide a reference for future structural damage.

Abstract: Based on nonlinear FEA software ANSYS, 3D simulation models of eighteen-type perforated plate that have different open-pore number was established. Analysis results indicate: Maximum equivalent stress of perforated plate mainly takes place on symmetry center of outer open-pore for open-pore area. With increasing open-pore number, maximum equivalent stress and each-direction maximum stress of perforated plate presents to enlarge trend. When open-pore number less than or equal to twelve, value of maximum equivalent stress mainly is decided by Z-direction maximum stress. When open-pore number greater than twelve, value of maximum equivalent stress mainly is decided by Y-direction maximum stress. When ratio m less than 2, with increasing ratio m, maximum equivalent stress and each-direction maximum stress of perforated plate presents to reduce trend. When X-direction and Y-direction open-pore numbe of perforated plate is basically equilibrium distribution, X -direction maximum stress is about equle to half of maximum equivalent stress.

Abstract: The band gap of a new two-dimensional phononic crystal was studied by the plane-wave expansion method. The two-dimensional phononic crystal is formed by square-shape array geometry of iron cylinders with square cross section inserted in an epoxy resin. The band gaps of different structures were calculated such as defect-free, single cavity crystal point defect states, crystal point defect states with (10) direction coupling, crystal point defect states with (10) direction next-nearest-neighbor coupling, and crystal point defect states with (11) direction next-nearest-neighbor coupling. Compared with that of defect-free, it is conclude that point defect is beneficial to the production of band gaps. The bandwidth of point defect is about 5 times larger than that of the defect-free crystal with the filling fraction F=0.4. In addition, the maximum number of band gap is in the crystal point defect states with (10) direction next-nearest-neighbor coupling. It will provide a theoretical reference for the manufacture of phononic crystal.

Abstract: The band gap of 2D perfect phononic crystal thin plate was investigated by plane-wave expansion (PWE), which is consist of copper embedded in the organic glass with a square arrangement. The band gap of straight linear defect, branching linear defect, and symmetrical linear defect are calculated by supercell plane wave method respectively. It is found that the bandwidth of defect structure will become narrow. Especially there is little band gap appearing for straight linear defect. As the filling fraction varied, the band gap width and the band gap number changed.

Abstract: It was analysed that the causes for the poor wear resistance of roller, fracture of roller and the surface of the roller flaking off were researched. Introducing CSP plant carried through technical and improved works about work roll material and using system in order to improve strip quality and decrease producing costs. It’s effective to resolve wear and breakage and spalling of the work roll and improve profile control and so on.

Abstract: A railway axle operated over 6×105 km has been detected by varied micro-examination methods in detail. The examination of Leeb hardness tester results showed that the hardness of the press-fit seats presented higher hardness than that of other sites. According to the micro morphological analyses by optical microscope (OM), scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDX), and profilometer on the surface at different press-fit seats, the most severe damage band was occurred at the inner edge of wheel seat near the gear seat. The transmission electron microscope (TEM) results indicated that the dislocation density of subsurface, beneath the axle surface about 20 μm, was much higher with a great deal of dislocation tangles, pile-ups and cellular structure formation. However, when the examination depth increased to 100 μm, no cellular structure can be founded, the dislocation density was very low, so the damage depth was less than 100 μm.

Abstract: Two kinds of surface heat treatment (wide-band laser surface quenching and high-frequency induction quenching) had been performed on a ferrous PM cam material for automobile applications. Microstructure, hardness and tribological properties of ferrous PM cam materials were investigated. After laser surface quenching, the sintered cam materials could obtain finer martensite microstructure and higher hardness value, compared to high-frequency induction quenching. Wear tests revealed the superior wear resistance and coefficient of friction of laser surface hardened specimens in comparison with high-frequency induction quenched ones. Laser surface quenching can be a more effective surface heat treatment to improve wear resistance of the sintered cam materials than high-frequency induction quenching. On the lower test loads (such as 50N), the wear mechanism of the surface quenched ferrous PM cam materials is dominated adhesive and abrasive wear, while on the higher test loads (such as 120N and 150N), it is primarily delamination wear and abrasive wear.

Abstract: Failure analysis on a strain clamp cracking on 220kV transmission line was carried out based on results of macro-observation, mechanical property examination and EDAX analysis. It is concluded that the main reason of the clamp failure lies in incomplete surface cleaning during wire crimping that cause large current flowing through steel cores, heating them and reduced their strength. In addition, oxidation due to residue water for insufficient baking also contributes to the failure. Finally suggestions were put forward.

Abstract: The structural properties and elastic constants of (B1-xCx)(N1-xCx) (x=0.0, 0.2, 0.4 and 0.6) are calculated by the ultra-soft pseudo-potentials within the generalized gradient approximation and local density approximation in frame of density functional theory with virtual crystal approximation. The elastic constants, the aggregate elastic modulus, poisson’s ratio, energy gap and hardness are computed too. The energy band structure, DOS, and Hellmann-Feynman stresses are also examined in details.