Applied Mechanics and Materials Vols. 385-386

Abstract: Convective heat transfer in microchannels of two-stage Y-branch bifurcation structures at different inlet velocities and branch angles were simulated, and the temperature, static pressure drop as well as the relationship between Reynolds Number (Re) and Nusselt Number (Nu) of fluid were compared and analyzed. The results indicate that the flow in microchannels with 30° branch angle has the minimum pressure drop for the velocities from 0.5 m/s to 2.5 m/s, while it comes at 60° for the velocities from 2.5 m/s to 3.5 m/s. It can also be found that the laminar-turbulent transition comes in advance compared with the common round channels. The critical Reynolds Number is found to be in 1997-2224, which is smaller than the known value of 2300. The Nu increases with increasing Re with a same trend for the different branch angles.

Abstract: This article studied about bending machine, adopted converse thinking for designing, transformed the bending machine then designed steel strip straightening machine, using this machine to make the deformed steel strip straighten. We used the 3 d modeling software SolidWorks to make a 3d model for the machine, then used the add-in cosmosworks of SolidWorks to make a simulation for main part, got the curve of stress, strain, and displacement of the part and provided a reference for the transformation of steel strip straightening machine.

Abstract: According to the flexible gears damage problem during the work process of the harmonic reducer, a FEM model of the flexible and wave generator was established. On the basis of the mechanics of materials and the finite element theory, a large number of numerical simulations by the use of the finite element software were made. The analysis shows that: the dangerous area is between the flexspline tooth rim and cylinder part. On this basis, the equivalent strain and equivalent stress at different transition fillet were discussed by the use of numerical simulation. The results show that: the equivalent strain and equivalent stress are decrease with the increase of the transition fillet. It provides a basis theory of the optimization design of the flexspline.

Abstract: Taking the minimum to cylinder thrust force, turntable force and boom force as the objective function then establish the optimization mathematical model of the verifying three nodes, taking BP Neural Network as the main method instead of the cumbersome formula derivation. This article puts forward a Hybrid Genetic Algorithm flow set of solving pareto optimal solution, It is achieved by mixed-using Niche Technology, Groups Sorting Technology. The optimal position of the arm verifying three nodes is conformed by programming using Matlab genetic algorithm toolbox. And the force of the fuel tank , boom and turntable is effectively mitigated. This gives a appropriate reference for the next boom verifying three nodes position to determine and the optimal design of similar structures in other engineering machinery.

Abstract: Shear displacement method is used to predict the settlement of the grouted pile in this paper. An empirical relationship is used to determine the improvement of shear modulus for the soil around the grouted pile. A parameter is also proposed to represent the improvement of the shear modulus for the grouted soil at the pile tip. Shear displacement method is modified to consider the influence of grouting. The detailed calculation process of the method is described and determine of the parameter is also given in the paper.

Abstract: By the statistical data the present situation of development and utilization was analyzed in coastal zone of Hebei Province. The characteristics were that multiple utilization type and integral sea economic system and Development and utilization of regional resources plenty. At the meantime, there were also many problems, such as, degeneration of sea biological resource, the erosion of tourist beach and the worse station of marine ecological environment. The paper proposes some suggestions, enhancing marine environmental protection and improving the quality of the marine environment, enhancing the protection and restoration of coastal wetland ecological system, establishing coastal planning system and optimizing the structure of utilization, enhancing dynamic monitoring and adjusting the planning of coastal development.

Abstract: In order to study the muddy costal evolvement processing of Hebei Province in about half century, the paper extracted costal information by 3 S technology from landform maps and remote sensing images. It concluded the station of different areas in different time. Then it studied the evolvement characteristics and the reasons of muddy coast deeply. Except that, it also analyzed the evolvement infections to the nearby coast of the marine engineering. The results were show that the beach was deposited into the sea with the speed from 1 m/a to 315 m/a which were difference about 314 m/a. From 1956 to 2006 the beach was deposited into the sea with the distance of 2.8 km and the average speed of 56 m/a. The muddy coast was deposited constantly. Before 1979 the beach was evolved with slow speed about 7 m/a. However, it was deposited in a high speed. For example, it was already 82 m/a in 1987. It was even in the speed of 315 m/a from 1991 to 1993. After that, it was slow down to 50 m/a from 1993 to 1998. And it was deposited in high speed about 113 m/a in 2006.

Abstract: Using modal analysis to train and bridges and piers for dynamics analysis, we got a theoretical solution. Using wireless sensor network architecture monitoring system for Bridges and piers of the acceleration and the settlement monitoring, in considering static load loading situation, through contrast train before and after the settlement of piers the quantity change and Bridges and piers acceleration size, draw piers vertical stiffness of the bridge vibration impact is not significant. Study of the bridge piers and transverse vibration characteristics, it is concluded that the piers lateral stiffness is far less than that of the vertical stiffness, piers and bridges in transverse have larger dynamic response to produce.

Abstract: Longyangxia reservoir is the key project for the upper reaches of the Yellow River by possessing the interannual regulation capability. This paper analyzes the runoff sediment characteristics since the operation of the reservoir on the basis of the hydrological data before and after the operation of Longyangxia reservoir. The study result indicates that the variation characteristics of water and sediment after the operation of the reservoir mainly include sharply-reduced peak discharge, varied annual runoff distributions, reduced annual runoff coefficient of variation, obviously-reduced quantity of sediment, varied sediment runoff relation; the operation characteristics namely annual storage in flood period, level period discharge high-flow year water storage and low-flow year water supplement of Longyangxia reservoir are the key affecting factors for the variation of water and sediment.

Abstract: For exploring the effect of particle dispersion and wind simulation in an urban surrounding. The tree was constructed with smaller numbers of polygons for saving the rendering time in real-time virtual environment simulation system. It was integrated into a real time pollution dispersion simulation system. Also a way was used for simulating the wind tree. The results show that this method is proper and efficient for simulating tree animation in real-time virtual environment simulation system.