Applied Mechanics and Materials Vol. 482

Abstract: During the flight of the long-range cruise missiles, aerodynamic heating can cause the temperature of the wing structure, fairing, missile body and other components to rise rapidly, along with serious structural vibrations. The thermal environment generated by aerodynamic heating significantly changes the mechanical properties of the materials and structure, including the elastic modulus, stiffness, and so on. The complex flight maneuver process will also produce high-temperature gradients, which affect the thermal stress field. Both of these impacts significantly affect the characteristics of the missile structures natural vibration. In this paper, thermal vibration joint testing was performed on two different wing structures of a high-speed missile under a thermal environment, and the vibration characteristics of the wing structure (e.g., the natural frequency) at various temperatures were obtained. The experimental results can provide a reliable basis for the safety design of the wing structure of missiles under high-speed thermal vibration conditions.

Abstract: This paper established the theoretical equations of transfer matrix method for frame shear wall structures to solve natural vibration and elastic response under earthquakes. Columns at each storey are combined into an equivalent shear member and shear walls are combined into an equivalent bending member. The structure is simplified as a double member system with the two members being coordinated by the in-plane infinite rigid floors. Transfer matrix of the structure was derived according to the fluctuated equations of equivalent members and the equilibrium and displacement compatibility conditions. After considering the boundary conditions at the bottom and top of structure, it presented the equations and method to solve seismic response, natural frequencies and modes of vibration of the structure. In comparison with FEM, it is a more convenient and universal method and is recommended for preliminary design of frame shear wall structures.

Abstract: Using three slab models (elastic plate, elastic membrane and rigid plate), the column displacement of one storey frames with different slab-hole ratio, column size and slab thickness under horizontal earthquake were calculated to investigate the driving and limiting factor on the in-plane deformation of floor slab. An influence factor concerning structure stiffness, floor slab stiffness and representative value of gravity load was proposed on the concept of fixed zone and deformed zone. A linear relationship between in-plane deformation and the influence factor was obtained based on the statistic data of 18 examples. Results show that the effect of out-of-plane stiffness of floor slab is very small and negligible and the in-plane deformation of floor slab can be kept within a reasonable range by balancing the structure stiffness of slab strips around the hole and deducing the length-width ratio of floor slab located at deformed zone.

Abstract: The dissertation shows the formation and failure characteristic of the dual functional hysteretic dampers. SAP2000 was used to analyze the natural period of vibration and vibration mode of structures, the story drift under frequent earthquake and rare occurrence earthquake with different arrangements of dampers and the energy dissipation of dampers. The results show that dual functional hysteretic dampers keep elastic state under frequent earthquake while enter plastic state before the structure under rare occurrence earthquake.

Abstract: The strong effect on ground damage and the serious earthquake-induced geological disasters are notable features of MS8.0 Wenchuan earthquake. This study obtained 993 earthquake geological disasters in Wudu District and Wenxian County of Gansu Province, by combining field investigation and interpretation of remote-sensing images. Then the characteristics of these geological disasters were investigated statistically using GIS techniques to determine how the occurrence of geological disasters correlated with intensity, distance from the rivers, slopes and elevations. The main results can be summarized as follows: (1) the geological disasters density increased with the increase of earthquake intensity; (2) the geological disasters triggered by earthquake show the feature of zonal distribution along the rivers; (3) the slope steepness is the main factor which controls the development of earthquake-induced geological disasters and most of the geological disasters are distributed with the slopes of 10 to 40 degree; (4) the earthquake-induced geological disasters have corresponding relationships with elevations, and most disasters occur with the elevation of 1000 to 2000 m.

Abstract: Pile-plank structure is a new type of structure which is suitable for soft soil area, it has several advantages: higher strength and stiffness, better stability, lower investment, and simple to construction. It is used widely at home and abroad, but the theoretical research lagged behind the project application. This paper take an example of a new constructed road beneath the Yongtaiwen High-speed Railway in soft ground which is adopted pile-plank structure. Firstly, analyze the settlement of pile-plank structure by theoretical calculation and numerical simulation, the result of two methods basically the same. Secondly, analyze the deformation of existing railway bridge foundation by constructing the pile-plank structure. The study of this paper will provide a reference to the foundation treatment measures in soft soil area.

Abstract: The harm of bridge deformation is serious, real time monitoring of bridge deformation is important to ensure the safe use. Over the years, the routine measuring method is unable to complete the multiple, dynamic monitoring. This paper discusses the method of multi-points instantaneous monitoring by using GPS technology, makes a great contribution to improve the technology of bridge detection, and has achieved good results.

Abstract: With the development of deep coal resources, rockburst, as a kind of typical underground dynamic disaster, always threats the production safety. Before the mining design, it is very necessary to forecast the possibility of the rockburst. This paper takes the Guo-tun coal mine for the object, considering the specific geological conditions, to predict the possible dangerous area where rockburst would happen. Through the comprehensive research and analysis, the paper would divide the 1312 working face into some probalble dangerous zones, namely strong shock hazard zones and medium dangerous impact zones, during gateway driving and stopping.

Abstract: The wind tunnel testing of large scale section model of the Forth Nanjing Yangzi River Bridge was conducted by the section model with a scale of 1:20. The details of the bridge girder could be simulated more precisely with a large scale. In the testing, a comparison was between the original girder cross section and the girder section without rails and tracks in the attack angle of +5°. On top of this, the main factor that causes the vortex-induced vibration of the girder was due to the installation of guide rail in the bottom of the girder. The control of vortex-induced vibration research was conducted concerning the installation of the guide rail.

Abstract: Traditional surrounding rockmass classification methods have disadvantages of relative narrow scope of application, most of the time the classification result needs some modifications by geological expert and field situation. Based on the surrounding rockmass classification methods of BQ system, the Bayesian network and corresponding uncertainty reasoning principle has been introduced to develop an expert system for surrounding rockmass classification. By combining prior knowledge of domain experts with worksite data recorder, we get the posterior probability density of most nodes. The field practices proved that the expert system has good applicability.