Advanced Materials Research Vols. 452-453

Abstract: In this paper, the relationship between the tensile ductility loss and the conditions including the exposure process and microstructures for the hot exposed TiAl alloys was researched. The critical temperature corresponding to the ambient tensile ductility loss to 0.8% was sensitive to the microstructure. It was 800°C/100h exposure for the near fully lamella microstructure. Due to the oriented lamella, the near fully lamella microstructure was benefit for forming the oxide layer rich in Al to present further oxidation of the matrix.

Abstract: This paper proposes an analytical tool that supports the design process of a disc spring valve system used in car dampers. The proposed analytical tool obtains a key design characteristic of a valve, which is the flow rate and the corresponding maximum stress level in the stack of plates, as a function of a pressure load. The tool is prepared based on the cases produced by a first-principle model using a finite element approach. The finite element model was calibrated based on experimental results to provide accurate results in the entire range of input parameters.

Abstract: The objective of the current study is the application of oceanic polymetallic nodules and cobalt-rich curst leaching residues. The phase composition, specific surface area and pore structure are measured. The experimental results show that the leaching residues with huge nano mineral particles have significant potential in environmental protection because of their large specific surface area and surface activity. The nano properties can be used for the disposal of heavy metal effluent with Cu2+, Pb2+ and Cd2+. And the influence of adsorption time, pH value and initial solution concentration on the adsorption effect are investigated. The maximum volume and adsorptive capacity of oceanic polymetallic nodules and cobalt-rich curst leaching residues to treat heavy metal waste water can be determined via the adsorption experiments.

Abstract: Based on the fluid dynamics and seepage mechanics, a mathematical analysis model in which the wellbore flow has been coupled with reservoir flow is established for the stepped horizontal well through the oil layers in three independent fault blocks. In the model, the reservoir flow is considered to be unsteady-state and wellbore pressure drop calculation model is established considering the influence of the on-way influx by using mass conservation principle and the theory of infinitesimal line congruence. Taking different curvature radius into account, a pressure drop calculation method is put forward for the layer-layer connective segments. With the mathematical analysis model, the flow behaviors of stepped horizontal well through multi-independent fault blocks has been analyzed and suggested by the calculation results, the optimal arrangement with good oil layer close to the heel side and the poor close to the finger is recommended for the minimum wellbore friction and the highest production.

Abstract: Analysis on monitoring data during construction of Chang Jiang Crossing Campaign memorial, the nonlinear method is used to get the fitting curve of stress-strain relation during construction, and the concrete constitutive relation of this project is acquired.

Abstract: Heat transfer and lubricant depletion in a HAMR system with multilayer disk substrate are numerically simulated in this study. Cases under two types of multilayer disk substrates with different materials on the top layer as well as different laser powers are examined. The results show the significant effects of the material property and the laser power. Compared with pure glass disk substrate, larger thermal conductivity of top-layer material in the multilayer disk substrate causes faster heat conduction and thus substantial reductions in the temperature increase and lubricant depletion on the top surface. Hence it is necessary and important to incorporate the real multilayer structure in modeling heat transfer and lubricant depletion in practical HAMR systems.

Abstract: The slide rail of the airfoil is the key structural component of the aircraft, and its wear reliability has important impact to the aircraft security. The traditional method to the slide rail wear reliability analysis is based on time parameter to establish the reliability function. In fact, the actual operating and environmental parameters in the slide rails have an important impact on its reliability. The proportional hazards model (PHM) method is proposed to study the affecting factors of the slide rail’s wear reliability; the method of principal component is used to make a quantitative description to those affecting factors. and the slide rail’s reliability model of its failure function and life distribution function are obtained under many factors affecting. Finally, a study is made to the wear reliability of some regional jet’s slide rail with the PHM method; the wear reliability model is got under the contact stress, hardness and roughness three affecting factors which meet the fact. So the more accurate wear reliability models can be got by the PHM methods, and that has a practical significance to improve the overall reliability of the aircraft.

Abstract: The traditional computer disassembly method can only be used to deal with some simply disassembly. Meanwhile the process of disassembly solution is mainly done by manual with the help of specialists and computers. To solve these problems, a new computer disassembly method, ontology-case-based reasoning (OCBR) is presented in this paper. In this method, the traditional disassembly method CBR is improved. The ontology, which is employed to build the case structure and to describe the individual case, is applied to the modified CBR. Due to the properties of ontology, the new method performs quite in theory and it paves the way of computer disassembly research in future.

Abstract: Effect of elastic modulus, yield stress and elongation percentage on buckling of spherical-cone diaphragm for positive expulsion tank has been analyzed by FEM based on orthogonal test, which highly decrease test numbers on the premise of validity of results. Numerical results are listed as follows: elastic modulus takes marked effect on buckling of diaphragm while yield stress and elongation percentage hardly affect buckling value of structure. As a result, larger elastic modulus will make for structural stability; different buckling values and modalities of structure are very close, which means that structural behavior is very sensitive to imperfections; local buckling of structure presents in column section, which avails to diaphragm inverting.

Abstract: In rotating machinery, vibration resonance with large amplitude and complex pattern occurs at critical speeds due to rotor imbalance and nonlinear effects. In this paper, a vibration control method is proposed for a rotor system supported by a ball bearing and an electro-magnetic bearing. In particular, a disturbance observer combined with the current delay estimation is implemented to improve the controller's ability of compensating for system's nonlinear effects and uncertainty. As a result, the rotor vibration is suppressed to very small amplitudes in the entire operating speed range. The proposed method is validated through numerical simulations and experiments.