Soil-structure interaction of offshore structures: time domain versus frequency domain analysis

1989 ◽  
Vol 26 (1) ◽  
pp. A43-A44
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Soil Structure ◽  
Domain Analysis ◽  
Offshore Structures ◽  
Frequency Domain Analysis ◽  
Domain Versus ◽  
Soil Structure Interaction ◽  
Structure Interaction

Frequency Domain Analysis of Multi-Degree of Freedom in Series Model SSI Effect with Translation and Rotation Input

2014 ◽  
Vol 1065-1069 ◽  
pp. 1457-1463
Author(s):  
Liang Fang ◽  
Qi Fang Wang
Keyword(s):  
Frequency Domain ◽  
Soil Structure ◽  
Correction Term ◽  
Mass Matrix ◽  
Frequency Domain Analysis ◽  
Degree Of Freedom ◽  
Soil Structure Interaction ◽  
Complex Matrix ◽  
Structure Interaction ◽  
In Series

Based on the multi-degree of freedom in series model, structural displacement amplitude formula is derived in the frequency domain under the translation-rotation input situation, this formula indicates that the soil - structure interaction (SSI) could be considered as adding a correction term M˜ to the mass matrix of the structure with the hypothesis of Rigid foundation. This corrected mass matrix is actually a complex matrix, which related to the input frequency and damping. Equivalent translation-rotation input is coupled with two translation input components U* and Θ*. Besides, we uses case analysis to explain the characteristics of soil - structure interaction (SSI) in frequency domain by the end of this paper.

DYNAMIC INFINITE ELEMENTS FOR SOIL-STRUCTURE INTERACTION ANALYSIS IN A LAYERED SOIL MEDIUM

2007 ◽  
Vol 07 (04) ◽  
pp. 693-713 ◽  
Author(s):  
C. B. YUN ◽  
S. H. CHANG ◽  
C. G. SEO ◽  
J. M. KIM
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Soil Structure ◽  
Interaction Analysis ◽  
Soil Structure Interaction ◽  
Shape Functions ◽  
Frequency Dependent ◽  
Structure Interaction ◽  
Infinite Elements ◽  
Stiffness Matrices

This paper presents the dynamic infinite element formulations that have been developed for soil-structure interaction analysis both in frequency domain and time domain by the present authors and our colleagues during the past 20 years. Axisymmetric, 2D and 3D layered half-space soil media were considered in the developments. The displacement shape functions of the infinite elements were established using approximate expressions of analytical solutions in frequency domain to represent the characteristics of multiple waves propagating into the unbounded outer domain of the media. The shape functions were determined in terms of the excitation frequency as well as the spatial and material characteristics of the far-field soil region. Thereby the element mass and stiffness matrices are frequency dependent. As for time domain analysis, the shape functions were further simplified to obtain closed-form frequency-dependent mass and stiffness matrices, which can analytically be transformed into time domain terms by the Fourier transform. The proposed infinite elements were verified using benchmark examples, which showed that the present formulations are very effective for the soil-structure interaction analysis either in frequency or in time domain. Example applications to actual soil-structure interaction problems are also given to demonstrate the capability and versatility of the present methodology.

scholarly journals Analysis of Three-Phase Wye-Delta Connected LLC

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3606
Author(s):  
Jing-Yuan Lin ◽  
Chuan-Ting Chen ◽  
Kuan-Hung Chen ◽  
Yi-Feng Lin
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Operation Time ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Complete Analysis ◽  
Plane Analysis ◽  
Analysis Methods ◽  
Three Phase

Three-phase wye–delta LLC topology is suitable for voltage step down and high output current, and has been used in the industry for some time, e.g., for server power and EV charger. However, no comprehensive circuit analysis has been performed for three-phase wye–delta LLC. This paper provides complete analysis methods for three-phase wye–delta LLC. The analysis methods include circuit operation, time domain analysis, frequency domain analysis, and state–plane analysis. Circuit operation helps determine the circuit composition and operation sequence. Time domain analysis helps understand the detail operation, equivalent circuit model, and circuit equation. Frequency domain analysis helps obtain the curve of the transfer function and assists in circuit design. State–plane analysis is used for optimal trajectory control (OTC). These analyses not only can calculate the voltage/current stress, but can also help design three-phase wye-delta connected LLC and provide the OTC control reference. In addition, this paper uses PSIM simulation to verify the correctness of analysis. At the end, a 5-kW three-phase wye–delta LLC prototype is realized. The specification of the prototype is a DC input voltage of 380 V and output voltage/current of 48 V/105 A. The peak efficiency is 96.57%.

scholarly journals Time Domain Implementation of Transmitting Boundaries in ABAQUS for Discrete Soil-structure Interaction Systems

2020 ◽  
Vol 5 (3) ◽  
pp. 447-462
Author(s):  
J. Rama Raju Patchamatla ◽  
P. K. Emani
Keyword(s):  
Time Domain ◽  
Soil Structure ◽  
Seismic Waves ◽  
Seismic Analysis ◽  
Discrete Models ◽  
Soil Structure Interaction ◽  
Finite Domain ◽  
Infinite Domains ◽  
Structure Interaction ◽  
Transmitting Boundaries

Soil-structure-interaction (SSI) analyses are essential to evaluate the seismic performance of important structures before finalizing their structural design. SSI under seismic condition involves much more complex interaction with soil compared to the dynamic loads having source on the structure. Seismic SSI analysis requires due consideration of site-specific and structure-specific properties to estimate the actual ground motion (scattered motion) experienced at the base of the structure, and subsequently the effects of the scattered motion on the structure. Most challenging aspect of seismic SSI analysis is to implement transmitting boundaries that absorb the artificial reflections of stress waves at the truncated interface of the finite and infinite domains, while allowing the seismic waves to enter the finite domain. In this paper, the time domain implementation of seismic analysis of a soil-structure system is presented using classical discrete models of structure and interactive force boundary conditions for soil. These models represent typical SSI systems- a single Degree of Freedom (DOF) of a spherical cavity with mass attached to its wall, a two DOF system consisting of a mass attached by a nonlinear spring to a semi-infinite rod on elastic foundation, and a three DOF system with additional DOFs for modelling the structural stiffness and damping. The convolution integral representing the force boundary condition on the truncated interface, is evaluated interactively using UAMP user-subroutine in ABAQUS and applied as concentrated forces at the interface (truncated interface) nodes of the bounded domain or generalized-structure domain. The verification problems presented in the paper show the satisfactory performance of the developed MATLAB code and ABAQUS implementation with FORTRAN user-subroutines. The classical phenomena associated with the dynamic soil-structure systems are discussed through the present work.

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