Applied Mechanics and Materials Vols. 444-445

Abstract: Faults are the commonly encountered large geological discontinuities in hard rock masses, many severe open pit slope failures are found to be closely associated with the faults presence nearby. Open-pit slope takes shape gradually as a rock unloading process accompanied by geostress redistribution, especially in a slope containing a fault. The finite difference code (UDEC) was employed as the analytical method in this paper and coulomb slip model was utilized to describe the properties of fault provided by UDEC. Parametric analysis has identified both the fault dips and fault locations relative to the open pit slope to be really critical for the open pit slope stability. The relationship of crest displacements, safety factor varying with these fault parameters was established. The distribution of plastic zone and displacement was graphically presented and the mechanisms such effects were discussed. These results offer a guideline in support design for an open-pit slope containing a fault.

Abstract: Imaging techniques allow the visualization of the heart valves, but do not yields any information regarding the load applied to the heart valve information that provides key clues to the cause of valve deterioration. Numerical simulation, which is able to replicate and understand the dynamics of the valve, would benefit studies on heart valves surgical repair and prostheses design. Modeling and simulation of heart valves dynamics is a challenging biomechanical problem. Many researchers have taken various approaches to model the heart valve. But systematical categorization and development tendency of their research have never been discussed before. This paper reviews their models and divides them into wet models or dry models, in the light of whether considering blood flow and valve interaction. These simulations also can be categorized as native heart valve or artificial heart valve simulation by a different model prototype. The critical issues for future research are presented.

Abstract: In this article, the typical phenomenon of bed armoring was firstly summarized based on both the field and experiment data, and then followed by the analysis on its internal influence on the reformation process to the balance status for the gravel-sand rivers. It was pointed out that this phenomenon is caused by the chosen of the flow, that the finer sediment particles are washed away and the coarser ones are left on the river bed surface. This phenomenon firstly restricts the start of the sediment particles on the bed surface, secondly increases the river bed surface resistance and reduces the flow velocity. The comprehensive effect of these two aspects leads to the final balance status for the gravel-sand river.

Abstract: Based on the experimental measured cooling curves and the boiling heat transfer theory, the inverse problem of nonlinear heat conduct equation for Steel 1045 quenched by different hardening media was established by functional analysis and finite element method, and the surface heat-transfer coefficients in continuous cooling during quenching were calculated by nonlinear estimate method. Then the constitutive model of Steel 1045 during quenching was established subsequently. Finally, the temperature field of Steel 1045 cylinder quenched by different hardening media was simulated by Finite Element Methods (FEM). Results show that the calculated temperature fields agree with the practical quenching process.

Abstract: For the development trend of advanced aircraft wind tunnel tests which require shorter cycle time and lower cost, a new wind tunnel testing process called Modern Design of Experiments (MDOE) is under development at NASA Langley Research Center. This paper presents a case study of application of Modern Design of Experiment methods in high speed wind tunnel tests based on the aerodynamic data of certain type of aircrafts. The full process including experiment design, execution, analysis of variance, and block design is described. Comparisons between MDOE predictions and OFAT measurements were made in the present study. The results show that the MDOE methods have well predictive capability to meet specific test objectives with less data volume, less cost and less time compared to the conventional OFAT methods, which means the MDOE approach established and used in this study is feasible enough to meet specific aerodynamic wind tunnel testing objectives in place of conventional OFAT methods.

Abstract: The aerodynamic heating and infrared radiation characteristics of BrahMos supersonic cruise missile were investigated. The aerodynamic heating was simulated using finite volume method, and the infrared radiation characteristics were simulated by reverse Monte Carlo method. Infrared radiation characteristics of missile surface were analyzed in different surface emissivity and flight altitudes, and the effects of environmental radiation and atmospheric attenuation were considered. The results show 8~14μm and 3~5μm environment radiation were approximately 10% and 2.4% of total radiation respectively, when the surface emissivity is 0.3. The proportion of environmental radiation reduces nearly half when the surface emissivity increases by 0.2.

Abstract: Karst rocky desertification is a major ecological disaster faced by the southeastern region of Yunnan Province, in China. The research of land use status in rocky desertification area is more and more concerned by human. Through remote sensing integrated survey ways to establish the spectral database of six kinds of typical land types, such as water, forest land, paddy field, grassland, dry land and bare land; then, Normalized Difference Vegetation Index (NDVI) processing and Tasseled Cap transformation processing for the spectral data; finally, the spectral characteristics and the variation of typical land types was analyzed and studied. The results indicated that, there are no significant differences of spectral of the six kinds of typical land types, after the processing of NDVI, the water, the forest land and grassland with larger vegetation coverage, and the paddy land, dry land and bare land with smaller vegetation coverage, can be well distinguish, but the distinction between forest land and grassland is bad, the distinction of paddy land, dry land and bare land is also bad; after the Tasseled Cap transformation processing, the dispersion degree of water, forest land, paddy field and grassland is better, the dispersion degree of dry land and bare land is a bit poor, need to be further studied. The remote sensing integrated survey and the analysis of spectral properties are important foundation for the Land Use / Land Cover Change (LUCC) and the dynamic monitoring of rocky desertification in southeastern rocky desertification region of Yunnan province.

Abstract: In dealing with high-resolution remote sensing image auto-identify classification, the traditional pixel-based and spectral statistical characteristics classification technology or method has some insurmountable difficulties. In this paper, object-oriented image analysis method is by application, the auto-identify classification rules are set up based the different remote sensing image characteristics that included such as spectral, texture, scale and so on. As a case study, a petroleum reserve base auto-identify classification is selected as an example and the target is identified, in a better effective result by applications of the object-oriented method. The result appraising analysis indicates that object-oriented classification method to identify automatically high-resolution remote sensing images pattern object can get a high precision. The method of object-oriented has a widely potential application for remote sensing image automatic-identify classification in times to come.

Abstract: L-shape traffic sign bar is composed of a stand column and a cantilever bar using bolted connection. The cross-section of stand column and a cantilever bar is closed thin wall with regular octagon and their cross sectional area is variable along axial line. The finite element simulation analysis for the bar is done under gravities and wind loads. Three-dimensional finite element model of bar is set up and stress field and displacement field is given under different load and their combination. Stress and displacement values of key parts are extracted and compared with theoretical calculation. Indicates that the theoretical calculation and finite element calculation is correct.

Abstract: With the rapid development of city, many large and medium-sized cities sprawl in urban space,triggering a series of socio-economic issues related to land-use. Based on RS and GIS, selected Kunming as study area for its typical representation of Yunnan plateau mountain cities, used the method of spatial quadrant orientation analysis, obtained the number and structure of construction land expansion in specific direction of study area in period of two different years, and calculated the intensity index and fractal dimensions of the urban expansion. Finally, according to local conditions, spatial expansion variations features of Kunming were analyzed systematically.