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.

An Efficient Mixed Finite Element Perfectly Matched Layer with Optimal Parameters Selection for Two-Dimensional Time Domain Soil-Structure Interaction Analysis

2021 ◽  
Author(s):  
Dong Van Nguyen ◽  
Jaemin Kim
Keyword(s):  
Finite Element ◽  
Time Domain ◽  
Soil Structure ◽  
Perfectly Matched Layer ◽  
Soil Structure Interaction ◽  
Numerical Analyses ◽  
Two Dimensional ◽  
Infinite Domains ◽  
Structure Interaction ◽  
Parameters Selection

Perfectly matched layer (PML) is known as one of the best methods to simulate infinite domains in many fields such as soil-structure interaction (SSI). The performance of PML is significantly affected by PML parameters selection. However, the way to select PML parameters still remains unclear. This study proposes a method for PML parameters determination for elastic wave propagation in two-dimensional (2D) media. The scaling and attenuation functions are developed in order to increase the accuracy and effectiveness of the PML. The proposed scheme is applied for a mixed PML in time domain. The finite element method (FEM) formulations of the PML are presented so that it can be easily applied to the existing codes. ABAQUS, a popular FEM code, is used for numerical applications in this study. The proposed PML is imported into ABAQUS by using a user-defined element (UEL) written in Fortran language. Six numerical analyses of SSI are implemented to prove the efficiency of the proposed PML. The numerical analyses cover many realistic problems, including free field, surface structure, and embedded structure problems. The results demonstrate the efficiency of the proposed PML in terms of the accuracy and computational cost.

scholarly journals Dynamic Analysis of Partially Embedded Structures Considering Soil-Structure Interaction in Time Domain

2011 ◽  
Vol 2011 ◽  
pp. 1-23 ◽  
Author(s):  
Sanaz Mahmoudpour ◽  
Reza Attarnejad ◽  
Cambyse Behnia
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Time Domain ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Structure System ◽  
Structure Interaction ◽  
Scaled Boundary Finite Element ◽  
Element Method

Analysis and design of structures subjected to arbitrary dynamic loadings especially earthquakes have been studied during past decades. In practice, the effects of soil-structure interaction on the dynamic response of structures are usually neglected. In this study, the effect of soil-structure interaction on the dynamic response of structures has been examined. The substructure method using dynamic stiffness of soil is used to analyze soil-structure system. A coupled model based on finite element method and scaled boundary finite element method is applied. Finite element method is used to analyze the structure, and scaled boundary finite element method is applied in the analysis of unbounded soil region. Due to analytical solution in the radial direction, the radiation condition is satisfied exactly. The material behavior of soil and structure is assumed to be linear. The soil region is considered as a homogeneous half-space. The analysis is performed in time domain. A computer program is prepared to analyze the soil-structure system. Comparing the results with those in literature shows the exactness and competency of the proposed method.

scholarly journals SSI AND SSSI EFFECTS IN SEISMIC ANALYSIS OF TWIN BUILDINGS: DISCRETE MODEL CONCEPT

2012 ◽  
Vol 18 (6) ◽  
pp. 890-898 ◽  
Author(s):  
Sadegh Naserkhaki ◽  
Hassan Pourmohammad
Keyword(s):  
Discrete Model ◽  
Soil Structure ◽  
Seismic Analysis ◽  
Numerical Study ◽  
Elastic Half Space ◽  
Soil Structure Interaction ◽  
Model Concept ◽  
Structure Interaction ◽  
Twin Buildings ◽  
Hard Soils

This paper presents a numerical study of soil-structure interaction (SSI) and structure-soil-structure interaction (SSSI) effects on response of twin buildings during earthquake excitations. The buildings are modeled as shear buildings and the soil is simulated by a discrete model representing a visco-elastic half-space subjected to earthquake acceleration. Equation of motion of twin buildings with different conditions, fixed based (FB), SSI and SSSI, are developed via an analytical procedure and solved numerically. Buildings responses are evaluated for aforementioned three conditions considering various soil types and compared together. One must say that soil causes change in distribution of responses throughout the buildings while ignoring soil interaction may lead to detrimental effects on buildings. Anyway, interaction between twin buildings with SSSI condition slightly mitigates soil unfavorable effects compare to one building with SSI condition. In addition, it is found that influence of soil is very significant for soft to stiff soils whereas negligible for hard soils.

Next Generation of Soil-Structure Interaction Models for Design of Nuclear Power Plants

2014 ◽  
Vol 9 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Alexander G. Tyapin ◽  
Keyword(s):  
Time Domain ◽  
Soil Structure ◽  
Power Plants ◽  
Near Field ◽  
Soil Structure Interaction ◽  
Current Status ◽  
Computational Techniques ◽  
Next Generation ◽  
Structure Interaction ◽  
Wave Effects

The author here shares his vision of next-generation models for seismic soil-structure interaction (SSI) analysis. These models should combine reasonable considerations of wave effects in half-infinite soil with a correct representation of nonlinearity in the structure, and in both the so-called near field, i.e., in that part of soil near a base mat, and in the soil-structure contact surface. The far field, i.e., all of the soil except for the near field, is treated as a linear horizontally layered medium, as is currently done in the well-known program SASSI. The importance of considering nonlinear effects even in very stiff structures like NPPs was shown by the March 2011 Great East Japan Earthquake that hit northeastern Japan’s Pacific coast. Although the idea of calculating SSI wave effects in the time domain has been around for several decades ago, current NPP design practices are linear. Next-generation SSI models should enable practical time-domain analysis. The author suggests a road map – the sequence of problems to be solved to achieve a proposed level. Some of these problems have already been solved, at least in principle, but other solutions are yet to be found. The author describes the current status of his research and ideas about implementing modern computational techniques such as parallel computation.

Influence of soil conditions on the seismic behaviour of two cable-stayed bridges

1995 ◽  
Vol 22 (5) ◽  
pp. 1021-1040 ◽  
Author(s):  
Mohamed Elassaly ◽  
Amin Ghali ◽  
Mamdouh M. Elbadry
Keyword(s):  
Soil Structure ◽  
Seismic Waves ◽  
Seismic Analysis ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Seismic Behaviour ◽  
Internal Forces ◽  
Time Required ◽  
Cable Stayed Bridges

The results of a case study of the internal forces caused by earthquake in two examples of cable-stayed bridges are presented. A comparison is made between the behaviour of a model in which the structure is idealized without the foundation system and a model in which both the structure and the supporting foundation are idealized. The effects of varying the soil conditions on the seismic response are assessed. Also, the effects of out-of-phase support movements, caused by the lapse of time required for the seismic waves to travel from one support to the other, are considered. It is concluded that the effects of these parameters are significant and should not be ignored in the seismic analysis of cable-stayed bridges. Key words: bridges, cable-stayed, dynamic, earthquake, internal forces, seismic, soil–structure interaction.

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