Applied Mechanics and Materials Vols. 448-453

Abstract: A phase-shifting algorithm, called a (4,4) algorithm, which takes four phase-shifting interferograms before a specimen is deformed and four interferograms after a specimen is deformed, is presented first. This method is most widely used for phase extraction. Its drawback limited it to be used in dynamic measurements. Also shown is an algorithm called a (4,1) algorithm that takes four phase-shifting interferograms before a specimen is deformed and one interferogram after a specimen is deformed. Because a high-speed camera can be used to record the dynamic interferogram of the specimen, this algorithm has the potential to retain the phase-shifting capability for ESPI in dynamic measurements. The quality of the phase map obtained using (4,1) algorithm is quite lower compared to using (4,4) algorithm. In order to obtain high-quality phase map in dynamic measurements, a direct-correlation algorithm was integrated with the (4,1) algorithm to form DC-(4,1) algorithm which is shown to improve significantly the quality of the phase maps. The theoretical and experimental aspects of this newly developed technique, which can extend ESPI to areas such as high-speed dynamic measurements, are examined in detail.

Abstract: This paper focuses on the multiple crack detection of steel pipelines using PZT-based guided waves. Numerical simulations of cracked pipes based on ultrasonic guided-waves are conducted by using the ANSYS finite element software. Based on the analysis of the reflected signal, the arrival time of the crack reflection waves are determined and the crack positions are accurately evaluated by the calculation of the travel time and group velocity of the PZT-based guided waves. The crack parameters are numerically altered to determine how the parameters impact the sensitive degree of the pipe crack damage. To validate the efficiency of the numerical simulation, an experiment of the multiple crack detection for the same parameter pipe with the numerical model is performed in the laboratory, and the results match well with the numerical simulation.

Abstract: The 3D flow filed of pump is calculated based on the Navier-Stokes equations and k-ε turbulence model, and the simulation results not only are beneficial to analyze the pressure pulsation around pump impellers, but also provide the boundary conditions for modal analysis of pump rotors. And then a novel fault diagnosis method is provided to simulate the nature frequencies of rotor, and research the relationship between rotor structure and rotor abnormal vibration based on the modal analysis. The research results show that, the frequency of water pressure pulsation mainly concentrated in 24.5Hz and 49.0Hz, especially when the blade angle of pump is greater than -2°; the nature frequencies of first order modal and second order modal are closely to the same 49.0Hz, so it is easy to induce the resonance, and the resonance is an important factor which lead to the severe vibration of pump.

Abstract: Coordinate measuring machine is a kind of test instrument in high precision. The accuracy is the important performance parameter. A method is proposed to realize the calibration of verticality error for adjacent linear axis about Articulated Coordinate Measuring Machine. The straightness error of two linear axis can be obtained based on Least Squares method through measuring points in their measuring range with a square box in high precision. So the verticality error can be calculated quickly according to mathematical equation. Experiment proves that the calibration method can get the verticality error rightly and effectively. At the same time, a foundation has been done for later error compensation about linear axis.

Abstract: Marine development activities have a great impact on the Marine environment. Laser transmission has been widely used in marine communications and imaging technology. Due to the different proportion of the chemical composition of seawater in each Ocean field, the laser transmission characteristic in seawater is also different. The transmittance has been measured and calculated in a constant transmission distance in this experiment, by four different wavelength lasers and different concentrations of the various chemical components of the seawater. Then the data were analyzed by transmission curve fitting. The conclusion of this experiment is: for relatively pure seawater, the transmission characteristics of blue - green laser is better than the purple or red laser, and green laser transmission characteristics is better than blue laser; for larger impurities seawater such as Tianjin seawater, the transmission characteristics of red laser is better than the other three wavelength laser.

Abstract: There are a lot of Permian volcanic rocks which are widely distributed in Tarim Basin. Because of the shielding effect of the volcanic rocks to the underlying structure, the distribution of the volcanic rocks in Tarim Basin is very important to the deep oil and gas exploration. However, with the progress of oil exploration in Tarim oil field in recent years, much more logging and seismic data is available. Based on the model of logging-seismic integrated identification, the distribution of the Permian volcanic rocks is revised by using the drilling, logging and seismic data. It shows that the rhyolite is mainly distributed in the north basin, and the basalt is widely distributed in the basin. Moreover, the basalt has larger area than which delineated by other people.

Abstract: Most of the natural crystal color distribution are more uniform, different shades, pastel colors, while in manual control is relatively stable under the conditions of the synthesis of crystal growth, its internal characteristics exhibited excessive uniformity, color uniform, uniform, gaudy, dull, colorant concentration is too high or too low, make crystal color appears too deep or too shallow phenomenon. This paper studies the characteristics of natural crystal detection methods.

Abstract: On the basis of discovered deposits in Qinling-Qilian-Kunlun metallogenic domain, the paper describes statistical characteristics of deposit size and ore-forming type to find the rule of the geological processes through describing mineralization time, types, scale and ore-bearing construction and draws a conclusion of regional mineralization.

Abstract: According to the outcrop, well data, geochemical and reservoir property in lower Yangtze area. This paper analyses the sedimentary environment, thickness, distribution, buried depth, organic matter content and types, maturity and reservoir characteristics of shale in WufengGaojiabian Formation of Upper Ordovician to Lower Silurian. The shale is formed in shelf sedimentary environments with large thickness and moderate depth. WufengGaojiabian Formation contains 0.5% to 1.0% of organic carbon, consistent with typeIandII kerogen. The Ro in rang of 1.5%~2.5%, indication high mature to over mature stage for gas generation. It has high brittleness of mineral content in this set of shale with rich micro-fracture. The thickness of shale, buried depth, organic carbon and maturity shows that GaoyouHaianJurong of Northern Jiangsu, JingxianNingguo of Southern Anhui, Linan of Western Zhejiang areas are considered favorable zones for shale gas formation.

Abstract: In order to study on the advanced detection technology and the sensitivity of the Fault geological structure based on induce polarization (IP) method, and analyze the hazards of the Fault geological structure in front of the excavation face of coal mine roadway. This paper establishes a simplified physical model of the structure and converts the model into an equivalent circuit for convenient study and then constructs an IP model of the Fault geological structure. The IP model is connected with the simulation detection model of geological abnormal mass to obtain the changed curves of the apparent resistivity and the apparent frequency under the IP mode. The curves obtained show that simulation detection results agree with the electrical parameters specified by the IP model. Therefore the basic idea of the electric method detection is verified, which will provide a feasible presupposition for the development of the coal (rock) IP effect based on the advanced detection instruments with the electric method.