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Equivalent linear model for seismic damage evaluation of single-degree-of-freedom systems representing reinforced concrete structures considering cyclic degradation behavior

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Earthquake engineering and engineering Vibration 2024年第3期23卷 637-648页

作者： Lulu Yan Ding-Hao Yu research center for Geotechnical and Structural engineering Technology of Liaoning Province Dalian UniversityDalian116622China State Key Laboratory of Coastal and offshore engineering Dalian University of TechnologyDalian 116024China

In this study,a novel equivalent damping ratio model that is suitable for reinforced concrete(RC)structures considering cyclic degradation behavior is developed,and a new equivalent linearization analysis method for implementing the proposed equivalent damping ratio model for use in seismic damage evaluation is *** this end,Ibarra’s peak-oriented model,which incorporates an energy-based degradation rule,is selected for representing hysteretic behavior of RC structure,and the optimized equivalent damping for predicting the maximum displacement response is presented by using the empirical method,in which the effect of cyclic degradation is ***,the relationship between the hysteretic energy dissipation of the inelastic system and the elastic strain energy of the equivalent linear system is established so that the proposed equivalent linear system can be directly integrated with the Park-Ang seismic model to implement seismic damage *** to the simplicity of the equivalent linearization method,the proposed method provides an efficient and reliable way of obtaining comprehensive insight into the seismic performance of RC *** verification demonstrates the validity of the proposed method.

关键词： degrading system equivalent linear system equivalent damping seismic damage RC structures

Analysis of Mixing of Pollutants in Water Waves and Currents

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China Ocean engineering 2007年第1期21卷 115-124页

作者：袁丽蓉沈永明唐军 Guangdong Province Key Laboratory of Coastal Ocean engineering Ocean Engineering Research CenterSun Yat-sen University State Key Laboratory of Coastal and offshore engineering Dalian University of Technology

A vertical two-dimensional turbulence numerical model for the interaction of waves and currents is developed in the paper based on the nonlinear two-equation k - ε model with the VOF method. The one-dimensional equivalent advection velocity and equivalent mixing coefficient are defined and the solving process is introduced： The pollutant concentration field, generated by an instant source in waves and currents, is calculated with the model, and then the equivalent advection velocity and equivalent mixing coefficient are obtained by calculating the time derivative of the mean and variance of pollutant concentration probability distribution. The effects of wave period and wave height on the equivalent mixing coefficient for waves and wave-currents are also investigated.

关键词： mixing wave-current turbulence model VOF method pollutant concentration

Effects of the wave directionality on wave transformation

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Journal of Hydrodynamics 2015年第5期27卷 708-719页

作者：柳淑学李金宣孙忠滨 State Key Laboratory of Coastal and offshore engineering Dalian University of Technology River and Harbor engineering Department Nanjing Hydraulic research Institute

A numerical model is proposed based on the time domain solution of the Boussinesq equations using the finite element method in this paper. The typical wave diffraction through a breakwater gap is simulated to validate the numerical model. Good agreements are obtained between the numerical and experimental results. Further, the effects of the wave directionality on the wave diffraction through a breakwater gap and the wave transformation on a planar bathymetry are numerically investigated. The results show that the wave directional spreading has a significant effect on the wave diffraction and refraction. However, when the directional spreading parameter s is larger than around 40, the effects of the wave directional spreading on the wave transformation can be neglected in engineering applications.

关键词： Boussinesq equations multi-directional waves wave directional spreading wave transformation

Reliability analysis of marine risers with narrow and long corrosion defects under combined loads

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Petroleum Science 2014年第1期11卷 139-146页

作者： Hu Xianwei Zhou Canfeng Duan Menglan An Chen offshore Oil and Gas research center China University of Petroleum China National Oil & Gas Exploration and Development Corporation research center of Energy engineering Advanced Joining Technology Beijing Institute of Petrochemical Technology

A marine riser,one of the most important components of offshore oil/gas transportation,needs to be designed to eliminate the risks caused by complex ocean environments,platform displacement and internal corrosion,*** this study,a new analytical-numerical assessment approach is proposed in order to quantitatively investigate the reliability of internally corroded risers under combined loads including axial tension and internal ***,an analytical solution of the limit state function of intact risers under combined loads is obtained,which is further modified by the non-dimensional corrosion depth （d/ t） for the risers with a narrow and long corrosion *** relationship between d/t and limited internal pressure is obtained by finite element analysis and nonlinear *** an advanced first-order reliability method （HL-RF） algorithm,reliability analysis is performed to obtain the failure probability,the reliability index and the *** results are further verified by Monte-Carlo importance *** proposed approach of reliability analysis provides an accurate and effective way to estimate the reliability of marine risers with narrow and long corrosion defects under combined loads.

关键词： Marine riser corrosion defect combined loads reliability calculation reliability verification

Numerical Study of Two-Dimensional Focusing Waves

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China Ocean engineering 2008年第2期22卷 253-266页

作者：李金宣柳淑学洪起庸 State Key Laboratory of Coastal and offshore engineering Dalian University of Technology Maritime and Ocean engineering research Institute

Two-dimensional focusing waves are generated and investigated by numerical method. The numerical model is developed by introducing the wave maker boundary on the high-order spectral （HOS） method proposed by Dommermuth and Yue in 1987 and verified by theoretical and experimental data. Some cases of focusing waves considering different parameters such as assumed focusing amplitudes, frequency bandwidth, central frequency and frequency spectrum are generated. Characteristics of the focusing wave including surface elevations, the maximum crest, shift of focusing points and frequency spectra are discussed. The results show that the focusing wave characteristics are strongly affected by focusing amplitudes, frequency bandwidth, central frequency and frequency spectrum.

关键词： high-order spectral method focusing wave monerical method

Design and Construction of System for Marine Geophysics Data Sharing Based on WebGIS

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Journal of Earth Science 2012年第6期23卷 914-918页

作者：王建村苏天赟李新仲李家钢李清平雷方辉李忠涛 The First Institute of Oceanography SOA research center of China National offshore Oil Corporation

A browser/server system has been developed for the purpose of marine geophysical data sharing based on WebGIS technology, which uses MapServer open source system and ORACLE Data- base Management System. The main steps during development, including system design and imple- mentation, are discussed in this article. The system can provide convenient, efficient, and interactive marine geophysical information sharing and visualization services through Internet or Intranet to im- prove data exchange and utilization.

关键词： WebGIS marine geophysics MapServer information sharing system.

Dynamic response of axially moving Timoshenko beams: integral transform solution

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Applied Mathematics and Mechanics(English Edition) 2014年第11期35卷 1421-1436页

作者：安晨苏健 offshore Oil/Gas research center China University of Petroleum-Beijing Nuclear engineering Program COPPE Universidade Federal do Rio de Janeiro

The generalized integral transform technique （GITT） is used to find a semianalytical numerical solution for dynamic response of an axially moving Timoshenko beam with clamped-clamped and simply-supported boundary conditions, respectively. The implementation of GITT approach for analyzing the forced vibration equation eliminates the space variable and leads to systems of second-order ordinary differential equations （ODEs） in time. The MATHEMATICA built-in function, NDSolve, is used to numerically solve the resulting transformed ODE system. The good convergence behavior of the suggested eigenfunction expansions is demonstrated for calculating the transverse deflection and the angle of rotation of the beam cross-section. Moreover, parametric studies are performed to analyze the effects of the axially moving speed, the axial tension, and the amplitude of external distributed force on the vibration amplitude of axially moving Timoshenko beams.

关键词： axially moving Timoshenko beam transverse vibration integral transform hybrid solution

Development of seismic force requirements for buildings in Taiwan

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Earthquake engineering and engineering Vibration 2009年第3期8卷 349-358页

作者： Juin-Fu Chai Tsung-Jen Teng Keh-Chyuan Tsai center for research on Earthquake engineering

This paper describes static and dynamic procedures to calculate seismic demand specified by the current seismic design code for buildings in Taiwan, which was issued in 2005. For design levels with a return period of 475 years, the design spectral response acceleration can be developed for general sites, near-fault sites and Taipei Basin. In addition, in order to prevent building collapse during extremely large earthquakes and yielding of structural components and elements during frequent small earthquakes, the required seismic demands at the maximum considered earthquake level （MCE, 2%/50 years） and operational level are also included in the new seismic design *** dynamic analysis procedures, both the response spectrum method and time history method are specified in the new seismic design code. Finally, procedures to generate spectrum compatible ground motions for time history analysis are illustrated in this paper.

关键词： building code seismic force requirement design spectrum spectrum compatible design ground motion site effect near-fault basin effect

Development of dynamic slip model for a shear crack

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Earthquake engineering and engineering Vibration 2010年第1期9卷 1-7页

作者： Juin-Fu Chai Tsung-Jen Teng center for research on Earthquake engineering

The objective of this paper is to develop a dynamic slip model for a shear crack under constant stress drop. This crack problem is formulated by a traction boundary integral equation （BIE） in the frequency domain and then solved by the hyper-singular boundary element method as well as the regularization technique proposed in this paper. Based on the spectral integral form of the kernel function, the unbounded term can be isolated and extracted from the hyper-singular kernel function by using the method of subtracted and added back in wave number domain. Finally, based on the inverse transformation from the frequency domain to the time domain, the time histories of crack opening displacement under constant stress drop can be determined. Three rupture models （simultaneous rupture model, symmetric bilaterally-propagating model and unilaterally propagating model） with specified time histories of stress drop are considered in this paper. Even though these three models will cause the same final slip shapes because of the same constant stress drop, the associated slip time functions differ significantly from each other during the rupture process.

关键词： dynamic rupture model traction boundary element method (BIE) hyper-singular boundary element method (HBEM) regularization technique