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991.
本文主要介绍了针对无锡轧钢厂设备基座的精密工程测量,并结合测量中的实际情况,重点提出如何避免和降低误差对大型机械设备测量的影响. 相似文献
992.
A three-dimensional general mathematical hydroelastic model dealing with the problem of wave interaction with a floating and a submerged flexible structure is developed based on small amplitude wave theory and linear structural response. The horizontal floating and submerged flexible structures are modelled with a thin plate theory. The linearized long wave equations based on shallow water approximations are derived and results are compared. Three-dimensional Green’s functions are derived using fundamental source potentials in water of finite and infinite depths. The expansion formulae associated with orthogonal mode-coupling relations are derived based on the application of Fourier transform in finite and infinite depths in case of finite width in three-dimensions. The usefulness of the expansion formula is demonstrated by analysing a physical problem of surface gravity wave interaction with a moored finite floating elastic plate in the presence of a finite submerged flexible membrane in three-dimensions. The numerical accuracy of the method is demonstrated by computing the complex values of reflected wave amplitudes for different modes of oscillation and mooring stiffness. Further, the effect of compressive force and modes of oscillations on a free oscillation hydroelastic waves in a closed channel of finite width and length for floating and submerged elastic plate system is analysed. 相似文献
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995.
The present paper is Part I of a series of three papers prepared by the authors on the methods useful for ultimate limit state assessment of marine structures, that have been developed in the literature during the last few decades. It is considered that such methods are now mature enough to enter day-by-day design and strength assessment practice. The aims of the three papers are to conduct some benchmark studies of such methods on ultimate limit state assessment of (unstiffened) plates, stiffened panels, and hull girders of ships and ship-shaped offshore structures, using some candidate methods such as ANSYS nonlinear finite element analysis (FEA), DNV PULS, ALPS/ULSAP, ALPS/HULL, and IACS common structural rules (CSR) methods. As an illustrative example, an AFRAMAX-class hypothetical double hull oil tanker structure designed by CSR method is studied. In the present paper (Part I), the ultimate limit state assessment of unstiffened plates under combined biaxial compression and lateral pressure loads is emphasized using ANSYS, DNV PULS, and ALPS/ULSAP methods, and their resulting computations are compared. Part II will deal with methods for the ultimate limit state assessment of stiffened panels under combined biaxial compression and lateral pressure using ANSYS, DNV PULS, and ALPS/ULSAP methods, and Part III will treat methods for the progressive collapse analysis of the hull structure using ANSYS, ALPS/HULL, and IACS CSR methods. 相似文献
996.
Hydroelastic analysis of pontoon-type circular VLFS with an attached submerged plate 总被引:2,自引:0,他引:2
This paper is concerned with the hydroelastic analysis of a pontoon-type, circular, very large floating structure (VLFS) with a horizontal submerged annular plate attached around its perimeter. The coupled fluid–structure interaction problem may be solved by using the modal expansion method in the frequency domain. It involves, firstly, the decomposition of the deflection of a circular Mindlin plate with free edges into vibration modes that are obtained analytically. Then the hydrodynamic diffraction and radiation forces are evaluated by using the eigenfunction expansion matching method which can also be done in an exact manner. The hydroelastic equation of motion is solved by the Rayleigh–Ritz method for the modal amplitudes, and then the modal responses are summed up to obtain the total response. The effectiveness of the attached submerged annular plate in reducing the motion of VLFS has been confirmed by the analysis. 相似文献
997.
A 2-phases neural prediction method for wave overtopping is developed. The ‘classifier’ predicts whether overtopping occurs or not, i.e. q = 0 or q > 0. If the classifier predicts overtopping q > 0, then the ‘quantifier’ is used to determine the mean overtopping discharge. The overtopping database set up within the EC project CLASH (De Rouck, J., Geeraerts, J., 2005. CLASH Final Report, Full Scientific and Technical Report, Ghent University, Belgium) is used to train the networks of the prediction method. 相似文献
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Spatial pattern and influencing factor of county-level industrial development in Liaoning Province of China 总被引:2,自引:1,他引:1
GAO Xiaona MA Yanji 《中国地理科学(英文版)》2008,18(1):24-32
County-level industrial development and structure upgrade is one of the most important issues of revitalizing old industrial base of China. After the cluster analysis on GDP per capita and GDP per area of each county in Liaoning Province, this paper finds the similarity of population size, land use intensity, and economic development of each county. Location quotient reflects the specialization intensity of industries in each county, and it also reflects the spatial differences of county-level industrial development. Economic development level is higher in the southeast than in the northwest of Liaoning, and the industry driving effect on county-level economy is apparent. The main influencing factors include location, industrial foundation and economic system reform, capital input level, knowledge and technology dissemination, conditions of domestic and overseas markets, population and labor force transfer. Industrialization is an important approach to urbanization for the counties in Liaoning Province. The proportion of agriculture is much higher in the northwest than in the southeast of Liaoning, so it will be take longer time for counties in the northwest of Liaoning to make industrialization, urbanization and modernization. 相似文献
1000.
本文提出我国北方含水量高的低洼地段公路工程中路基填方铺设方法,重点研究了材料配合比不确定、工程地质条件复杂、充填施工质量不易控制等问题,进行二灰土击实与压缩性能的试验研究,得出了石灰、粉煤灰和土3种充填材料的配合比,并针对工程特点,提出了确保施工质量的措施。室内试验及现场施工均取得了较满意的结果,该研究为公路路基填方提供了可借鉴的经验。 相似文献