检索结果-南通市图书馆

Multilevel Optimal Design of Prestressed Lightweight Concrete-Steel Platform Structures

在线全文

学校读者我要写书评

暂无评论

China Ocean engineering 2002年第1期17卷 69-78页

作者：王立成宋玉普康海贵王兴国 State Key Laboratory of coastal and Offshore engineering Dalian University of Technology

The concrete-steel platform structure is rather complicated because it involves such materials as concrete, reinforcing bars, steel, and so on. If the traditional dimension optimization method is employed, the optimal design of the platform will meet many handicaps, even it cannot be implemented at all. The multilevel optimal design approach is an efficient tool for the solution of large-scale engineering structures. In this paper, this approach is applied to the optimal design of a concrete-steel platform, which is formulated as a system level optimal design problem and a set of uncoupled substructure level optimal design problems. The process of optimization is a process of iteration between system level and substructure level until the objective function converges. An illustrative example indicates that this method is effective in the optimal design of concrete-steel platforms.

关键词： concrete-steel platform multilevel optimal design objective function design constraints

Longshore Currents of Random Waves on Different Plane Beaches

在线全文

学校读者我要写书评

暂无评论

海洋工程：英文版 2003年第2期17卷 265-276页

作者：邹志利王淑平邱大洪王艳王风龙董国海 State Key Laboratory of coastal and Offshore engineering Dalian University of Technology

Model tests and numerical calculation of longshore currents and wave heights produced by irregular waves on two beaches with slopes of 1:100 and 1:40 are studied. The cross-shore distributions of longshore current velocities and wave heights are given and the influences of wave heights, wave periods, and beach slopes on longshore currents are discussed. The discussion is also made on the influences of different eddy viscosity coefficients on the numerical results of longshore current velocities.

关键词： coast current current coasts wave breaking

Tensile and Flexural Properties of Ultra High Toughness Cemontious Composite

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2009年第4期24卷 677-683页

作者：李贺东徐世烺 State Key Laboratory of coastal and Offshore engineering Dalian University of Technology

The tensile and flexural properties of polyvinyl alcohol （PVA） fiber reinforced ultra high toughness cementitious composite （UHTCC） were investigated. The composite, tested at the age of 14 d, 28 d and 56 d, shows extremely remarkable pseudo strain hardening behavior, saturated multiple cracking and ultra high ultimate strain capacity above 4% under uniaxial loading. Also, the corresponding crack widths are controlled under 50 um even at 56 days age. In the third point bending tests on thin plate specimens, the composite shows ultra high flexural ductility and multiple cracking on the tension surface. The high ultimate flexural strength/first tensile strength ratio of about 5 verifies the pseudo strain hardening behavior of UHTCC. SEM observation on fracture surfaces provides indirect evidence of optimal design for the composite.

关键词： pseudo strain hardening cementitious composite multiple cracking ductility SEM

Experimental Study on the Performance of Twin Plate Breakwater

在线全文

学校读者我要写书评

暂无评论

China Ocean engineering 2011年第4期25卷 645-656页

作者：郭传胜张宁川李艳阳李靖波房卓崔成 State Key Laboratory of coastal and Offshore engineering Dalian University of Technology

The wave transmission characteristics and wave induced pressures on twin plate breakwater are investigated experimentally in regular and random waves. A total of twenty pressure transducers are fixed on four surfaces of twin plate to measure the wave induced dynamic pressures. The spatial distribution of dynamic wave pressure is given along the surface of the twin plate. The uplift wave force obtained by integrating the hydrodynamic pressure along the structure is presented. Discussed are the influence of different incident wave parameters including the relative plate width B/L, relative wave height Hi / a and relative submergence depth s / a on the non-dimensional dynamic wave pressures and total wave forces. From the investigation, it is found that the optimum transmission coefficient, Kt occurs around B/L = 0.41 - 0.43, and the twin plate breakwater is more effective in different water depths. The maximum of pressure ratio decreases from 1.8 to 1.1 when the relative submergence depth of top plate is increased from -0.8 to ＋0.8.

关键词： twin plate wave pressure vertical wave force relative submergence transmission coefficient

Numerical simulation of solitary wave propagation based on MPS method

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2007年第3期26卷 121-128页

作者： LI Shaowu YU Zhi＇ an XIONG Zan Department of Port and coastal engineering Tianjin University Tianjin 300072 China

The concept of candidate particle set is introduced in the MPS gridless numerical method to generate neighboring particle set ma- trix, which can reduce the CPU time to 1/11 of that before introduction. The Bi-CGSTAB （bi-conjugate gradient stabilized） algorithm is applied to solving the Poisson pressure equation, by which the solving speed is significantly accelerated. The process of solitary waves propagating over a numerical flume and interacting with a vertical wall is simulated. The simulated results of water surface elevation are in good agreement with the analytical solution as well as the measured data. The predicted maximum values of the run-up of solitary waves with various relative incident wave heights agree well with the measured results.

关键词： MPS method candidate particle set Bi-CGSTAB algorithm solitary wave

A large-scale wave-current coupled module with wave diffraction effect on unstructured meshes

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2014年第7期57卷 1331-1342页

作者： WANG Ping ZHANG NingChuan State Key Laboratory of coastal and Offshore engineering Dalian University of Technology

Based on the extended mild-slope equation,a large-scale wave module is *** combining the eikonal equation and the modified wave action equation,the wave model can account for diffraction in most situations such as in the lee of islands and breakwaters,and using unstructured meshes provides great flexibility for modelling the wave in the complex geomorphology of barriers and islands,also allowing for refinement of the grid resolution within computationally important *** numerical implementation of the module is based on the explicit second-order upwind finite-volume schemes in geographic space,the Flux-Corrected Transport(FCT)algorithm in frequency space and the implicit Crank-Nicolson method in directional *** three-dimensional hydrodynamic module is then modified to couple with the wave model,where the wave readily provides the depth-dependent radiation stress and the wave-induced turbulence coefficient for the current fields,and the wave propagation takes into account the current-induced advection,refraction and diffraction of wave energy and the effect of water *** applicability of the proposed model to calculate Snell’s Law,wave transformation over the breakwaters and the elliptic shoal,wave propagation over the rip current field and the undertow on a sloping beach is *** results show that the present model makes better predictions of the near-shore wave propagation and complex three-dimensional(3D)near-shore circulation driven by the waves,considering analytical solutions and experimental values.

关键词： mild-slope equation large-scale wave refraction-diffraction wave-current interaction unstructured meshes

Numerical Analyses of Bearing Capacity of Deep-Embedded Large-Diameter Cylindrical Structure on Soft Ground Against Lateral Loads

在线全文

学校读者我要写书评

暂无评论

China Ocean engineering 2006年第4期20卷 623-634页

作者：栾茂田范庆来 State Key Laboratory of coastal and Offshore engineering Dalian University of Technology

Presented in this paper is a three-dimensional plastic limit analysis method of bearing capacity of the deeply-embedded large-diameter cylindrical structure in the cross-anisotmpic soft ground. The most likely failure mechanism is assumed to be of a composite rupture surface which is composed of an individual wedge in the passive zone or two wedges in both active and passive zones near the mudline, depending on the separation or bonding state at the interface between the cylindrical structure and neighboring soils in the active wedge, and a truncated spherical slip surface at the base of the cylinder when the structure tends to overturn around a point located on the symmetry axis of the structure. The cylindrical structure and soil interaction system under consideration is also numerically analyzed by the finite element method by virtue of the general-purpose FEM software ABAQUS, in which the soil is assumed to obey tie Hill＇s criterion of yield. Both the failure mechanism assumed and the plastic limit analysis predictions are validated by numerical computations based on FEM. For the K0-consolidated ground of clays typically with anisotropic undrained strength property, it is indicated through a parametric study that limit analysis without consideration of anisotropy of soil overestimates the lateral ultimate bearing capacity of a deeply-embedded cylindrical structure in soft ground in a certain condition.

关键词： cylindrical structure limit analysis of plasticity soil anisotropy soft ground FEM

AN IMPROVED NUMERICAL METHOD FOR CALCULATIONS IN WAVE KINEMATICS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2009年第6期21卷 826-834页

作者： SUN Yi-yan LIU Shu-xue LI Jin-xuan State Kay Laboratory of coastal and Offshore engineering Dalian University of Technology Dalian 116024

The prediction of wave kinematics is a necessary basis for ocean engineering design. In this article, an improved method to calculate the wave kinematics especially in the crest region is presented. This method is based on the local approximation method. According to one measured wave surface, the proposed solution focuses on a Fourier series expansion in a somewhat larger segment of the wave surface record. The horizontal and vertical kinematics under the wave crest can be directly predicted. Good agreement between the numerical results and the theoretical Stokes waves verifies the validity of the numerical model. The effectiveness of the numerical method is also proved by the calculation of the wave kinematics of the laboratory focused wave groups.

关键词： Fourier series expansion wave kinematics focused wave

Strain analysis of buried steel pipelines across strike-slip faults

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2011年第5期18卷 1654-1661页

作者：王滨李昕周晶 State Key Laboratory of coastal and Offshore engineering Dalian University of Technology

Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of *** study the failure mechanism more accurately,a refined strain analytical methodology was proposed,taking the nonlinear characteristics of soil-pipeline interaction and pipe steel into *** on the elastic-beam and beam-on-elastic-foundation theories,the position of pipe potential destruction and the strain and deformation distributions along the pipeline were *** with existing analytical methods and three-dimensional nonlinear finite element analysis,the maximum axial total strains of pipe from the analytical methodology presented are in good agreement with the finite element results at small and intermediate fault movements and become gradually more conservative at large fault *** position of pipe potential failure and the deformation distribution along the pipeline are fairly consistent with the finite element results.

关键词： strike-slip fault buffed pipeline nonlinear pipe-soil interaction analytical formula strain analysis