Applied Mechanics and Materials Vols. 90-93

Abstract: One trench for agricultural irrigation next to the Hu-Ning Intercity Railway viaduct section were tested and analyzed in order to obtain the effect of ground vibration isolation when CRH trains run on. The result shows that with the decreasing train speed, the peak value of ground vibration velocity decreases and the main frequency of ground vibration heightens. Trench has lowpass filtering effect on ground surface vibration. The slower the train speed, the better the effect of isolation, but the phenomenon that ground surface vibration increases before trench is more obvious. When the length of trench is much longer than the length of train, the number of carriages has little effect on vibration isolation effect of the trench. When railways are built, consulting with nearby residents and department of agriculture, and the trench’s length, depth, breadth and the distance to railway should be designed reasonably. And then the trench in addition to meet need of irrigation, but also has very good effect on vibration isolation.

Abstract: This paper analyzes the deformation features and possible “true” displacements of a reservoir slope near the Laxiwa hydropower station in the upstream of Yellow River using the neural network. The error correction is also discussed for the results calculated by the neural network. The displacement prediction and feedback analyses of the reservoir slope in this paper show that the slope deformation and failure has occurred before water impoundment.

Abstract: The purpose of data fusion is to combine and process the data of multi-sensors, thus to obtain much more exact and reliable results than that of the single sensor. An improved data fusion method for commensurate sensors is presented in this paper. It overcomes the shortcoming of the traditional consensus algorithm with two sensors, which has different confidence distance while measuring in different precision. The relation matrix is fuzzified to avoid the subjective error in determining the threshold value. The results of numerical simulation shows that the improved method can make full use of the effective information from the sensors and it can help to improve the accuracy of measurement. Even when parts of sensors are affected or fully disabled, it still can get correct diagnosing results in damage identification.

Abstract: The influence of source distance on the characteristics of acoustic emission (AE) signals from mortar and normal concrete were investigated in this research. To collect AE signals of high signal to noise, which can be used in AE research for cement-based materials, the influence of source distance on the characteristics of AE signal were analyzed. The results showed that distance made a significant influence on the characteristics of AE signal from cement-based material, such as rise time, counts, peak amplitude and average frequency.

Abstract: We demonstrate the design of the recyclable photocatalyst based on ferromagnetic (FM) ZnO- TiO₂ core-shell nanowires (NWs). Since the band gaps and band edge energies of bulk ZnO and anatase TiO₂ are equal to each other within about 45mV, TiO₂ and ZnO can form an p-p+ heterojunction free of band discontinuities and with a built-in potential. The resulting radial field will increase hole density in the TiO₂ layer while reduce hole concentration at the interface between the core and the shell, which in turn will decrease the rate of recombination in the photocatalytic TiO₂, and hence increase the efficiency of photocatalyst. On the other hand, the NWs with FM cores can be easily collected and refreshed using solenoid and suitable for the recyclable usage of the NW catalyst

Abstract: Soil salinization is a most important factor to influence agriculture in arid area. There is a dire need to monitoring the soil salinization information based on Chinese own satellite data. In the study, a remote sensing classification method of soil salinization land based on knowledge discovery and decision-making process that is benefit to arise classification precision through a decision tree method has been constructed. The result shows that near 80% area of the entire county has suffered soil salinization with different grade. The percent of heavy, middle and light grades soil salinization area are 11.29, 20.53 and 49.01 respectively.

Abstract: The two-period (1990 and 2010) remote sensing images in Longkou City are selected in this article.The temporal and spatial variation of land use in Longkou City is monitored and analyzed by Geo-information Tupu and transfer matrix. Results show that the pattern of the land use change of Longkou City from year 1990 to year 2010 has changed a lot. The relatively stable area accounts for 74.33%, Garden land increases a lot and the increasing area is 14706.53 hm2,accounting for 16.48%. In the past ten years, there is no large-scale land arrangement, so the reason of the change is the economic interests.

Abstract: A low tower cable-stayed bridge with a span of 30m+60m+120m+60m+30m had been built before Guidelines for Seismic Design of Highway Bridge was promulgated. Because of its impor¬tance and specificity, it is necessary to do research on seismic performance of this bridge. According to the numerical analysis, it is found that the structural response exceeds the allowance and the bridge might be destroyed if earthquake happened. Here, energy dissipated technology is chosen to cope with this problem. But traditional lead shear damper hasn’t the capabilities of large deformation for some reason and can not be applied to bridge engineering in general case. In this article, a new type of lead shear damper with capabilities of large deformation is used to achieve energy dissipation. Through comparing, it is found that the damping effect of this new damper is as good as that of viscous damper. And the damper has no problem with leakage and metamorphism. What’s more, it is much cheaper than vis¬cous damper. So, lead shear damper has a good prospect in bridge damping.

Abstract: The numerical simulation analysis, by using senior nonlinear finite element analysis software MSC.Marc, was achieved in this paper for the tie-replacing procedures of a steel tube tied-arch filled with concrete. Through this analysis, the control parameters were accurately determined for the installing of new ties and the removing of old ties. Results of numerical analysis ensured the bridge structure stable during the replacement, made the construction of safe and convenient, and played a guiding role in the maintenance and reinforcement. The successful experience could be referenced by other similar projects.

Abstract: Established space dynamic analysis model of nonlinear structure in accordance with the unique mechanical characteristics of Lowpylon Cable-stayed Bridge. As the Example for the program about 90+128 meters spacing lowpylon Cable-stayed Bridge of houhu in Wuhan,Simulated the whole process of automobile loading bridge ,calculated eigenvalues of moving loads. Adopted computing skills,using nonlinear supperposition theory analysed time-history and discussed the influence about vibration of transverse and longitudinal because of different velocity. The results show that the research using nonlinear supperposition method to study the dynamic response of Cable-stayed Bridge under moving load is reasonable and effective.