Applied Mechanics and Materials Vols. 475-476

Abstract: Urban underground pipelines are the lifelines of the city. With the acceleration of city modernization, the traditional way to design and manage pipeline plans which relies on 2D diagrams has been difficult to secure the normal operation of the city. In this paper, a standard automatic 3D pipeline modelling process is proposed; a way to manage massive 3D scenes by scene graph is raised; three patterns of 3D integrated visualization are suggested; innovative stereo displays of pipeline analysis results are thought out. Eventually, a 3D urban underground pipeline plan aid system has been developed. At present, the system has been used in Xicheng Bureau of the Beijing Municipal Planning Commission, providing valuable decision-making information for urban underground pipeline network planning and management.

Abstract: Almost all the fields use tree modeling in society, so it analyses the tree modeling in the academic circles. But it is difficult to find an efficient tree modeling method because its own complexity and wind, rain acting on tree. The object suffers rain power that the force calculated by momentum theorem. And then compare the value of rupture limit to Young modulus. It is determined object to fracture or sway. Then it constructs tree dynamic modeling in the nature.

Abstract: Primary mirror (PM) supporting system design is one of the key components to the design of a telescope. This paper presents applications of extended multi-point supporting structures that are employed in ground based theodolites, 3 points positioning-9 points supporting system and 18 points supporting system. A number of theoretical studies have been performed using Finite Element Analysis (FEA) on each supporting system, in which the extended multi-point supporting system to 0.6-m and 1-m diameter primary mirror is particularly focused. Analyzing Zerodur major mirrors with a diameter to thickness ratio less than 7.3, deformation due to supporting gives an RMS value less than 6-nm which is 24% of the design requirement of 60-nm. Series of experiments have also been conducted using 4-D interferometer. The deformation due to supporting of major mirror has been predominantly suppressed mainly by deformation during the fabrication process. This indicates that the above supporting systems perform an excellent task under given conditions.

Abstract: The roof model of the palace timber buildings was established according to the construction technology of the Ying-tsao fa-shih. Based on its analysis of dynamic behavior with shaking table test and ANSYS finite element software, the dynamic behavior of structure and its maximal response under different conditions were gotten, and also the dynamic magnification factor of the beams layer and the whole structure were gotten, at last the results got by shaking table test was compared with the numerical simulation. Research shows that the nature frequency of the model is 1.486 Hz which is much bigger than that of the whole structure; the maximal displacement of beam layer gradually increases with the increase of ground motion intensity and the height of structure; the vibration isolation performance of semi-rigid tenon-mortise joints in rare earthquake (400gal) is better than that in moderate earthquake (220gal) and frequent earthquake (110gal); the dynamic magnification factor between layers was about 1, and roof 0.9 or so.

Abstract: This article provides an example of the calculation of eccentrically compressed reinforced concrete elements operating under dynamic loads and fire effects. Dynamic coefficient depending on temperature and strain rate, the results of experiment varies widely from 0.4 to 0.8. It is possible to reveal the influence of the dynamic effect on the reduction of the bearing capacity of the pylon and fire and columns of 40%.

Abstract: The dynamics of atmospheric pressure glow discharges in coaxial tube have been numerically studied by a self-consist, one-dimensional fluid model. An asymmetric discharge current pulse, which operated in glow mode, was obtained in the cylindrical geometry. As the frequency or the voltage peak is increased, the discharge transits into a period-two state.

Abstract: The attitude information is indispensable to realize the full range of navigation part. Besides, in aerial remote sensing, photogrammetry and laser scanning, we can get exterior orientation elements by attitude of device. Based on Picard solving quaternion differential equation realized the real-time dynamic attitude matrix updating and attitude solution. Comparison of IMU three axis output, calculation error of heading is 0.036183°, pitch is 0.007969° and roll is 0.009627°. Finally, verify the feasibility and stability of Picard solving attitude.

Abstract: The oscillation for certain third-order nonlinear neutral delay dynamic equations on time scales is discussed in this article. By using the generalized Riccati transformation and the inequality technique, three new different sufficient conditions which ensure that every solution is oscillatory or converges to zero are established. The results obtained essentially generalize and improve earlier ones.

Abstract: The traditional model for average support probability often assumes that component life is exponentially distributed. But the different types of components in electromechanical integration system may follow different non-exponential distributions. In order to solve the problem, we formulate the random event of support failure as the event of system shutdown with service parts in short supply. We show system shutdown can be formulated as a Markov process and we develop a practical method for solving the problem of how converting non-exponential distribution to exponential. In the base of above, we develop an average support probability model for series system with arbitrary-life-distribution units. By simulating the operation of a non-exponential distribution system in Extendsim software, we compare the result with our model and prove the correctness of it.

Abstract: Nowadays, tree modeling is used in various fields of social widely. Existing tree modeling method ignore trees their own feature so that it construct modeling could not express lifelike tree morphology and then depict the effects attitude of wind and rain and other natural factors in nature. This paper discusses tree dynamic modeling to express the tree multicolored under the wind or rainfall area. Using the theorem of momentum to calculate the instantaneous momentum, and compared to rupture limit, and then depict the state of tree break or mutual extrusion.