Applied Mechanics and Materials Vols. 353-356

Abstract: A re-parameterization transformation is discussed. With this re-parameterization transformation, a polynomial curve can be reformulated as a rational curve, with a parameterization that is optimal in the sense that no other rational representation of the curve approximates more closely arc-length parameterization. Computing instances are included.

Abstract: Hydration heat, one of the most severe factors, makes great effects on the mass concrete construction, especially on bridge structures and dam structures. Based on the experiment, this paper adopted large-scale finite element method with ANSYS software to analyze the transient temperature field during concrete placement. The atmosphere temperature, construction method, thermodynamics as well as material parameters (cement hydration heat, elastic modulus) were taken into account. The results clarity the distribution characters and process of the hydration heat temperature and stress. Besides, the computational and experimental results were compared. The results indicate that the surface cracks occur due to the large stress which is induced by the extensive internal and external temperature difference. As a result, references are provided to avoid harmful temperature cracks during pier construction period.

Abstract: This paper deals with a numerical and experimental approach trying to solve some suspension insulator string failure problems, experienced on a quadruple bundle transmission line. The FEM of the system is presented in order to analyze the dynamic behavior of the system. Then an experimental setup is designed according to the similarity by means of FEM analysis. The bending strain level on the insulator string experienced to subspan oscillation is tested in the experimental span, and the frcature mechanism is validated. Finally, the solution adopted to limit the subspan oscillation within safe values is presented and discussed.

Abstract: Having the entrance/exit depot line of Guogongzhuang metro depot of Beijing metro line 9 as the background, ballasted track-soil model is established and simulated. The accuracy of the model is proved comparatively high. Taking the nearby building as the research object, effects of structure characteristics modification of the building on slab vibration are discussed. The results suggest that: The trend of the vibration levels of slabs changing with the floors is the same as that of the benchmark example after changing the structure characteristics of the building. As the dimension of columns increases and the performance of the concrete is better, the vibration levels of the building decrease obviously. As the thickness of slabs increases, the effect is much more complicated. The vibration level of each slab increases from basement 2 to the 14^th floor by 0.02 to 8.4dB. The vibration level of each slab decreases from the 15^th floor to the top floor, and the vibration levels are 0.8 to 9.9dB lower than that of the benchmark example.

Abstract: Low-pylon cable-stayed bridge is a new style, which has developed rapidly in the 1980s. Changshan Bridge is the first cross-sea cable-stayed bridge in the cold area of China and is establishing in Dalian city of Liaoning province now. This paper takes this bridge as the background, analyzing the influence on structure of geometric nonlinearity. Cable sag and large displacement effect are considered in the analysis. And then, applying large common software-ANSYS to create finite element model to carry on the static calculation which are under the dead weight and secondary dead load, especially emphasize structure large displacement effect. At last, the linear and nonlinear analysis is made. Conclusions are obtained according to the comparison between those results. Study the feasibility of using ANSYS to realize geometric nonlinear analysis on structure.

Abstract: This essay stimulates multiple sets of constructional elements and a variety of constraints with the help of ANSYS. Collecting and sorting out the first principal stress simulation of each model which is under the same load .Calculating the theoretical value of each constructional element under the first principal stress by using related formulas in mechanics of materials. The optimal form of constraint was gotten by comparing the simulation value with the theoretical value. The conclusion could provide theoretical basis for simulating structural constraints of ANSYS.

Abstract: Based on the octree decomposition method and the hierarchical bounding boxes method, an accurate collision detection algorithm integrating spatial decomposition and spatial occupancy is proposed. Through an example of a three-tiered steel building, a quantitative analysis approach to roughly judging the relative efficiency is obtained by comparing the algorithm with several others. The analysis results indicate that the proposed integrated algorithm is applicable to accurate collision detection of building structures. In addition, focusing on two special collision detection issues in construction projects, namely collisions of pipeline projects, and collisions between dynamic construction machines and building components during construction process, the integrated algorithm is also improved according to the corresponding characteristics. A real construction project of a medical building is used to verify the feasibility and effectiveness of the improved algorithms. The results illustrate that the improved algorithms can solve the existing problems and provide satisfied efficiency.

Abstract: The author researches the conversion of N_xO_y and C_xH_y through a numerical simulation of the NTP and catalytic reactor, which contains the following factors: for instance the effect of flow, electrode diameter, reaction temperature, reaction time, voltage, frequency and electrode spacing, etc. The simulation results of NTP and catalytic reactor on the organic waste gas (N_xO_y and C_xH_y) reaches its optimum purification effect when the parameters are fixed as below: the flow is 5 l/s, the electrode diameter is 0.3 mm, the reaction temperature is 350 K, the reaction time (radial velocity) is 0.4 m/s,the voltage is 40 Kv, the frequency is 80 Hz.

Abstract: The STAR-CCM+ technology is also used to analyze the location and number of vents in hull coating plant in the case of constant air volume. By means of numerical simulation and mathematical model theory, this paper makes a comparison of air distribution in the working area of this plant, and found the interior velocity and temperature field vary with different location and number of vents. Specifically speaking, the lower position and improper number of vents can lead to unevenness of the internal thermal environment and imbalance of wind speed in the working area. This study provides simulated basis and technical references for the better coating operations in suitable environment, which is significant for putting forward the improvement, optimizing the quality of the coating operation and saving energy.

Abstract: The integration of the aircraft design process requires careful management of the computer information system to avoid the use of different standards yet to allow changes to be incorporated as the design develops. The aircraft project manager has to control the total system design. This requires different knowledge and skills to that of the traditional chief designer. Several different software suites have been developed to meet the requirements of 'computer-aided design'. Each of the major manufacturing companies has incorporated a specific CAD system which it standardizes for use in all the sections of the company; and they require subcontractors to be able to use a similar system.