Applied Mechanics and Materials Vols. 52-54

Abstract: A 5-stage helico-axial multiphase pump was tested for studying its performance. The multiphase pump was tested on the conditions of different speed and different gas volume fraction (GVF). According to the test result, performances of the pump were analyzed. And the effects of speed and GVF to differential pressure and efficiency as well as to power of the pump were analyzed at the same time, so some conclusions were made basing of the above research and some of them are very helpful for the future application on the oilfield.

Abstract: The entropy weak solution of the isentropic gas dynamics system has the important background of physics and mechanics, and the study on the interaction of nonlinear elementary wave not only had direct mechanics significance, but also was an effective method to clarify the structure of the weak solution. We explored the overtaking problem of the centred rarefaction wave and the shock wave for isentropic gas dynamics system with polytropic gas in γ=3. By using Riemann invariants, the characteristic method and convexity analysis for the envelope of compression waves, we clarified the physical state after interaction for the overtaking problem in the interaction location, and proved that the locally structure of the entropy weak solution was piecewise smooth.

Abstract: The rapid quantification method of glucose aqueous solution was established by using the Fourier transform infrared spectroscopy (FTIR) and attenuated total reflection (ATR). Model optimization and wavenumbers selection was investigated based on Savitzky-Golay (SG) smoothing. For the whole spectral collecting region 4500-600 cm-1 and the fingerprint region 1600-900 cm-1, Partial least squares (PLS) models without and with SG smoothing were established respectively. The optimal model was on the fingerprint region with SG smoothing of 1st order derivative, 2nd degree polynomial and 73 smoothing points, PLS factor, RMSEP, RP, were 4, 0.331 mmol/L, 0.999 respectively. Based on 19 absorption peaks of the subtracted spectra of glucose aqueous solution for de-ionized water, all possible wavenumber combinations were used to establish discrete multiple linear regression (MLR) models respectively, the optimal wavenumbers combination was 3084, 1034, 991 (cm-1), RMSEP and RP were 0.459 mmol/L, 0.997 respectively. It could provide valuable references for designing spectrophotometer system in special spectrometer and further for glucose analysis of the complex system. To get the stable prediction results, all models and results here were obtained based on the average data on 50 different divisions of calibration set and prediction set.

Abstract: It is higher superior of the caterpillar mobile robots to others types of robots in unknown complex environment, the advantage is apparently; but the issue is, it is difficulty in exact analyzing the posture of the robot kinematics model. In this paper, the new ideas proposed in the view of this issue, on the solution of posture motion model in the non-structural environment, motion agencies is transformed by the equivalent mechanism transformation, a fixed posture on the ground movement model is established by the screw theory. The posture model of non-holonomic constraints multi-joint caterpillar robot could be transferred into a kinematics model of parallel mechanism posture. Besides, the posture control method on over-obstacle stability is proposed, analyzing with the controlling experiment.

Abstract: The aim of this paper is to present the method of identifying the impact location on the plate. This basic research has the purpose to achieve the human-interaction technology based on the signal processing, piezoelectric materials, and wave propagation. The work concerning the location identification of a single impact on the plate has been previously studied by means of the time frequency analysis applied to accelerometer signals. In this paper, a novel approach for the location identification of the discrete impact is presented to investigate the feasibility of applying to a human-interaction system. For the identification of the impact location, the major axisymmetry mode of the Lamb wave on the plate is used for this work.

Abstract: A low noise duplex bush chains with split rollers was developed through changing roller structure to reduce noise of bush roller chains. The split rollers could absorb more impact energy, mitigate meshing impact and reduce chain drive noise. The noise generated by different types of duplex bush roller chains was carried out to test in same speed, low noise characteristics of duplex sleeve chains with split rollers was verified. By analysis of testing data, noise level of duplex sleeve chains with split rollers compared with that of the other duplex bush roller chains was reduced by the average 3 ~ 8dB, and low 10 ~ 13dB than that of 16A simplex sleeve roller chains. The chains made chain drive significantly improve in the working environment, with steady transmission, strong bearing, low noise, and a significant noise reduction was achieved.

Abstract: A theoretical study is presented herein on the perforation of the cone-nosed projectiles against bi-layered laminated composite aluminum alloy foam target. Bi-layered targets were arranged according to the mass density and thickness of foam material. The dynamic cavity expansion theory is applied to formulate analytical model. The perforating process can be divided into 8 stages. The analytical equations during every stage are derived to evaluate the final penetration depth and penetration resistance during the whole perforating process. Penetrating depths, velocity limits and residual velocity of projectile are analyzed. The effect of mass density of target material and the layer thicknesses on the penetration resistance and capacity of absorbing energy are investigated. The results demonstrate that configuration of laminated targets and the initial kinetic energy play important roles during the perforating processes.

Abstract: The given article studies the changes in thermal cycle and cooling rates of steel 30ХГСА weld joints at various distances from the weld center using modern thermal imaging equipment. The analysis of the experimentally obtained and calculated thermal cycles showed that the calculated cycles almost match the experimental ones in terms of quality but the time distribution of calculated values is 4-5 times smaller than that of the experimental ones. On the base of experimental results and theoretical investigation of the thermal cycles for fusion-welding in СО2 we have developed an improved formula for calculating heat conduction for machine single-pass welding. The difference between the calculated and experimental values of thermal fields does not exceed 10%.

Abstract: A three dimensional unstructured model was established and estuaries with different cross sectional divergence rates and different bed form were designed to study the estuary geometric feature effecting on salt-fresh water mixing in estuary. The model dispersing 3d domain into unstructured triangular and/or quadrangular elements, has good flexibility to simulate complex bank. By analyzing the horizontal and longitudinal distribution attributes of velocity and salinity field, the effects of cross section divergence rate, the bottom elevation of mouth and the slope inside estuary on salt water intrusion in estuary are studied. The result could act as design basis for the engineering projects which will change estuary’s bank shape or bed form such as estuary regulation and channel dredging.

Abstract: Introduction of a water synchronous hydraulic system , the special physical and chemical properties for water and the position requirements in Synchronous control , mathematical models is based on the system and simulate the position control performance of the system . there is a reference value of water hydraulic field application of synchronous controlling.