Advanced Materials Research Vols. 204-210

Abstract: The stabilization problem of nonlinear systems with Hopf bifurcations is studied in this paper. The link between a feedback law and a center manifold is obtained. By choosing a feedback law that stabilizes the dynamics of a center manifold, then it can stabilize the full order system. The simulation shows the effectiveness of the method.

Abstract: In the paper, the housing of a specific type of sheet-metal type hydraulic torque converter is modeled and simplified by means of three coordinate measuring instrument and UG software. Moreover, the housing fatigue life is simulated and predicted by FLUENT and MSC software platform according to the three-dimensional flow theory. Further tests are launched to research and analyze the fatigue life and testify the simulation. It is proved that the simulation result basically complies with the experiment result. Upon less than 100,000 pressure circulations, the dilatation undergoes linear variations. In this phase, the housing suffers from elastic deformation. When the number of pressure circulation exceeds 100,000, the housing undergoes plastic deformation. Besides, the part of impeller and turbo housing with the largest curvature discontinuity, and the connection between the center and the bearing bushing shall bear a short service life.

Abstract: Through more than 30 Km field survey in an important project of diversion water, there were many samples been taken from channel concrete lining and sluice pier to study failure mechanism of concrete due to sulfate attack at low value in soft water. The microstructure of concrete and mineral component of separated material was investigated by X-ray diffraction (XRD) and scanning electron microscope-energy dispersion X-ray analysis (SEM-EDAX). Then the processor of chemic action and physics action was analysis. Engineering situation shows that concrete can be failure quickly due to sulfate attack in soft water. Only one winter the strength of concrete reduced to zero. The test shows the failure mechanism is contact dissolution associating sulfate attack. The contact dissolution makes condition for sulfate attack. The concrete expand due to sulfate attack accelerate contact dissolution. So concrete can be failure in a short period.

Abstract: A generalized filled function method is developed in this paper to solve nonsmooth constrained global optimization problem. Theoretical properties of the proposed function is investigated, and a solution algorithm is proposed. Numerical experiments are also reported in this paper. The preliminary computational results show that the proposed method is promising.

Abstract: In this paper, an improved Kalman filter algorithm was proposed by two kinds of anti-perturbation method which were derived according to the perturbation theorem of inverse matrix. Furthermore, direction-correcting has been merged into this algorithm by using multiple hypothesis testing theory which can detect the current direction of a target. Experiments which were based on indoor positioning have shown that the improved algorithm(named IKF) has great performance.

Abstract: A new experimental project was adopted for the special hot-work of pure Cu, which used the execrable condition of high-temperature and high-pressure environment in bore of artillery. Specimen of Cu was prepared from rotating band of sand projectile which had been shot out. Microstructure of Cu after instantaneous extrusion and high speed friction were observed by scanning electron microscopy (SEM). Severe plastic deformation (SPD) and recrystallization phenomena were researched. The analysis results are as follows. At the beginning of SPD, under the instantaneous compression, the surface layer of metal became fibrous tissue with the phenomena of work-hardening. Many oblique strip grains appeared between equiaxed grains and fibrous tissue. With the continuous plastic deformation, temperature of metal improved rapidly under the high speed friction. Recrystallization occurred on the outermost part of fibrous tissue due to heating, so sub-grains gradually became homogeneous equiaxed grains. In addition, SPD had little effect to the inner structure, which is full of equiaxed grains still. All above work could support the research of microstructure of Cu on certain extreme particular environment.

Abstract: Glass reinforced plastic (GRP) pipeline has good characteristics of anti-corrosion, anti-scaling and it is widely used in the oil transportation pipeline. Analyze the water hammer characteristics of GRP pipeline is essential to ensure the safety operation of the pipeline. The water hammer mathematic model for GRP pipeline is built through combing the general water hammer mathematic model and prosperities of GRP pipeline. The solving method of the model is discussed based on the method of characteristic. Ultimately, the simulation results show the GRP pipeline can reduce the peak pressure and pressure fluctuation frequency as well as increase the low pressure caused by water hammer compared with steel pipeline. The GRP pipeline has a better capability to reduce the harms brought by water hammer than steel pipeline.

Abstract: Hyperspectral imaging (400-1000nm) and artificial neural network (ANN) techniques were investigated for the detection of nitrogen content changes of rape leaf. Measuring SPAD value of rape leaf by using SPAD (Soil and Plant Analyzer Development).A hyperspectral imaging system was established to acquire hyperspectral data. Principal component analysis(PCA) was used to obtain principal component images, as well as to select the optimal wavelength(s). ANN was applied to establish the model between the spectral reflection values and SPAD values. The prediction results were obtained for the nitrogen content of rape leaf with the correlation of prediction of R=0.9237. The results show that the hyperspectral imaging has good classification on different nitrogen content of rape leaf.

Abstract: Aerodynamic design rules of unconventional layout loitering aircraft against the issue of stall in low speed flight were proposed in this paper. Using the SST k-ω two equations turbulence model, the stalling characteristics of the loitering aircraft were studied. Based on the low speed flow field of the loitering aircraft without the deflexion of the helm, aerodynamic parameters such as lift, drag, pitching moment and yawing moment in different workings were calculated. Analysis of the results shows that the loitering aircraft designed has good stalling capability whose critical angle of attack is 18 degrees. The loitering aircraft has good longitudinal and lateral stability under different angle of attack.