Applied Mechanics and Materials Vol. 160

Abstract: Rotating instability can be observed in the tip flow region of axial compressor stage while stable operation. In order to investigate the noise characteristics in a multi-stage axial compressor, the noise inner compressor casing is measured simultaneously with the vibration of the rotor blades on a high pressure compressor component rig testing. An azimuthal mode analysis and theoretical formulation of the rotating source mechanism are applied to the unsteady pressure at the casing wall immediately upstream of the inlet plane of the rotor. It is shown that RIs might be described by a group of superimposed modes. This is the reason why RIs can be identified as an amplitude increase in a frequency band. The mode orders of RI are consecutively numbered riseing with frequency. The frequency in the source frame (ω^N) closed to the frequency in the rotating frame (ω^N) can be got well recovered. The results presented in this paper can be a reference for further understanding of the characteristics of unsteady flow field and the effects of the high intensity sound waves on the rotor blades.

Abstract: A difference method to order decision for least square in trend fitting is proposed in this paper. When the least square is used for fitting trend, choosing the proper order is important for trend fitting accuracy. We can use difference n times to obtain difference result data, and the mean value can be taken as decision criteria. Comparing with the threshold value, when the mth difference result mean is smaller, the trend fitting order for least square can be set to m. Simulation processing results show that this method resolve the problem of order decision for least square in trend fitting, and the method has high accuracy for trend extraction.

Abstract: The residual stresses due to the mismatch between metallic bond coat and ceramic top coat lead to a collapse of all thermal barrier system. For measuring residual strain in elastic multilayer materials, the incremental hole-drilling strain-gauge method was studied. The main stresses, which is interrelated with the residual strain, is resolved on planes that are normal to a deep hole. In order to link the surface strain to the residual stress, calibration coefficients were obtained by the finite element method. The result shows that the coefficients depend on the substrate and the type of coating, the strain gauge used and the size of the step drilled.

Abstract: The reducer device is a complicated mechanical system composed by several important components, which should establish model before manufacture and carry out dynamic simulation of movement mechanism. It could assemble component model into mechanical system by using the assembly module of Solidworks. Compared with three-dimensional assembly modeling processes that was created by the traditional CAD. This study has calculated and listed the key parameters of mechanical design and established a full model of assembly. The resulting model contribute to technical analysis for future manufacture.

Abstract: In order to investigate the renovation and expansion of coastal high-pile on the possible environmental impact of erosion and deposition, the changes of ocean current field and bottom erosion before and after the current field of renovation and expansion were simulated in use of an average two-dimensional vertical flow theoretical simulation model and Dou theory, based on ocean current Speed, flow and other measured data, integrated hydrological, meteorological and other historical information. The results showed that after the construction of Suanshan Dock , the increased siltation of Yang gong-shan Dock and Budui Dock code were approximately 1m and 0.5m respectively. Due to the high pile and bridge-type structure of high-pile dock , although the construction of Suanshan Dock would cause coastal area occurring a certain flow pattern changes , there were not significantly changes to the topography of basin . The underwater slope area would remain in a relatively stable state.

Abstract: The influence of aluminum doping on the ionic conductivities and phase transition in the La2Mo2–xAlxO9-δ(x = 0.1, 0.2, 0.3) oxide-ion conductors has been investigated by XRD, DSC and dielectric relaxation measurements. The results indicate that the solubility of Al3+ in La2Mo2O9 sample is about 10mol%, Al3+ can not suppress the α/β phase transition in the La2Mo2O9, and the aluminum substituted La2Mo2O9 has a higher conductivity in whole temperature than that of pure La2Mo2O9.

Abstract: In this paper, the AD-MUSIC method for far-field source localization is introduced to near-field, a two-dimensional MUSIC method based on ambiguity function distribution is proposed. Further, a novel AD-ROOT-MUSIC method is proposed for near-field source localization which constructes two matrices based on ambiguity function. They both have high accuracy and resolution for the bearing and range estimation of non-stationary signals in the near field, even when the signal-to-noise ratio (SNR) is low. The effectivity of the methods are validated by simulations.

Abstract: Due to the huge amount of image data transmission conditions and the existing relative low, makes the image compression become inevitable, key technology of image compression for image data transform to transform the quantitative data, as well as to the quantitative data, after the entropy coding.And this article USES the 2 d Mallat of wavelet image compression algorithm is a kind of common image compression method of wavelet image compression algorithm is the core.

Abstract: A study of buffeting control of the E-dong Bridge Using an indiscrete tuned mass damper (ITMD) system is performed in this paper. Different from the traditional multiple tuned mass damper (MTMD) system which is fixed along the main span of bridge discretely, this indiscrete tuned mass damper is attached to the centre region of the bridge’s main span continuously. A three-dimensional finite element model of E-dong Bridge, is completed by the software of ANSYS. By comparing the vertical and lateral buffeting response of bridge without dampers, the control efficiency of ITMD and MTMD is confirmed.