Semi-realistic tight-binding approach to spin-orbit physics at interfaces

A. Manchon,S. Ghosh,G. Manchon,A. Hajr,A. Hariri 한국자기학회 2019 한국자기학회 학술연구발표회 논문개요집 Vol.29 No.2

Strain-based seismic failure evaluation of coupled dam-reservoir-foundation system

Hariri-Ardebili, M.A.,Mirzabozorg, H.,Ghasemi, A. Techno-Press 2013 Coupled systems mechanics Vol.2 No.1

Generally, mass concrete structural behavior is governed by the strain components. However, relevant guidelines in dam engineering evaluate the structural behavior of concrete dams using stress-based criteria. In the present study, strain-based criteria are proposed for the first time in a professional manner and their applicability in seismic failure evaluation of an arch dam are investigated. Numerical model of the dam is provided using NSAD-DRI finite element code and the foundation is modeled to be massed using infinite elements at its far-end boundaries. The coupled dam-reservoir-foundation system is solved in Lagrangian-Eulerian domain using Newmark-${\beta}$ time integration method. Seismic performance of the dam is investigated using parameters such as the demand-capacity ratio, the cumulative inelastic duration and the extension of the overstressed/overstrained areas. Real crack profile of the dam based on the damage mechanics approach is compared with those obtained from stress-based and strain-based approaches. It is found that using stress-based criteria leads to conservative results for arch action while seismic safety evaluation using the proposed strain-based criteria leads to conservative cantilever action.

Nonlinear analysis of contemporary and historic masonry vaulted elements externally strengthened by FRP

Gehan A. Hamdy,Osama A. Kamal,Mohamed O.R. El-Hariri,Tarik S. El-Salakawy 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.5

This paper addresses numerical modeling and nonlinear analysis of unreinforced masonry walls and vaults externally strengthened using fiber reinforced polymers (FRP). The aim of the research is to provide a simple method for design of strengthening interventions for masonry arched structures while considering the nonlinear behavior. Several brick masonry walls and vaults externally strengthened by FRP which have been previously tested experimentally are modeled using finite elements. Numerical modeling and nonlinear analysis are performed using commercial software. Description of the modeling, material characterization and solution parameters are given. The obtained numerical results demonstrate that externally applied FRP strengthening increased the ultimate capacity of the walls and vaults and improved their failure mode. The numerical results are in good agreement with the experimentally obtained ultimate failure load, maximum displacement and crack pattern; which demonstrates the capability of the proposed modeling scheme to simulate efficiently the actual behavior of FRP-strengthened masonry elements. Application is made on a historic masonry dome and the numerical analysis managed to explain its structural behavior before and after strengthening. The modeling approach may thus be regarded a practical and valid tool for design of strengthening interventions for contemporary or historic unreinforced masonry elements using externally bonded FRP.

Estimation of Probable Damages in Arch Dams Subjected to Strong Ground Motions using Endurance Time Acceleration Functions

M. A. Hariri-Ardebili,H. Mirzabozorg 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.2

In the present paper, nonlinear behavior of mass concrete using the smeared crack approach is combined with the Endurance TimeAnalysis (ETA) method for estimation of probable damages in arch dams when they are subjected to strong ground motions. ETAmethod is a time-history based dynamic pushover procedure for seismic analysis of structures in which they are subjected to a set ofintensifying artificial ground motions called Endurance Time Acceleration Functions (ETAFs). Numerical model of an arch damreservoir-foundation system was excited in maximum credible level using real ground motions and equivalent ETAFs. Cracked areaswithin the dam body are selected to compare ETA results with conventional nonlinear time-history analysis. Results show acceptableconsistency between two methods while using ETA method reduces the total cost of analysis considerably. In addition, continuumseismic performance of dam was evaluated when it’s subjected to ETAFs.

Nonlinear analysis of contemporary and historic masonry vaulted elements externally strengthened by FRP

Hamdy, Gehan A.,Kamal, Osama A.,El-Hariri, Mohamed O.R.,El-Salakawy, Tarik S. Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.5

This paper addresses numerical modeling and nonlinear analysis of unreinforced masonry walls and vaults externally strengthened using fiber reinforced polymers (FRP). The aim of the research is to provide a simple method for design of strengthening interventions for masonry arched structures while considering the nonlinear behavior. Several brick masonry walls and vaults externally strengthened by FRP which have been previously tested experimentally are modeled using finite elements. Numerical modeling and nonlinear analysis are performed using commercial software. Description of the modeling, material characterization and solution parameters are given. The obtained numerical results demonstrate that externally applied FRP strengthening increased the ultimate capacity of the walls and vaults and improved their failure mode. The numerical results are in good agreement with the experimentally obtained ultimate failure load, maximum displacement and crack pattern; which demonstrates the capability of the proposed modeling scheme to simulate efficiently the actual behavior of FRP-strengthened masonry elements. Application is made on a historic masonry dome and the numerical analysis managed to explain its structural behavior before and after strengthening. The modeling approach may thus be regarded a practical and valid tool for design of strengthening interventions for contemporary or historic unreinforced masonry elements using externally bonded FRP.

Seismic behavior of three dimensional concrete rectangular containers including sloshing effects

Mirzabozorg, H.,Hariri-Ardebili, M.A.,Nateghi A., R. Techno-Press 2012 Coupled systems mechanics Vol.1 No.1

In the present paper, the three-dimensional model of a typical rectangular concrete tank is excited using an artificial and a natural three components earthquake ground motion and the staggered displacement method is utilized for solving the coupled problem of the tank-contained liquid system in time domain. In the proposed method, surface sloshing of the liquid is taken into account in addition to the impulsive term and the appropriate damping values are applied on both of them. The resulted responses are compared with those obtained from the ABAQUS finite element software. It is found that the convective term affects responses extensively and must be considered in seismic design/safety assessment of storage tanks. In addition, the utilized method for solving the coupled problem is stable during the conducted general dynamic analyses and is able to capture the expected phenomena.

Force density ratios of flexible borders to membrane in tension fabric structures

Asadi, H.,Hariri-Ardebili, M.A.,Mirtaheri, M.,Zandi, A.P. Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.6

Architectural fabrics membranes have not only the structural performance but also act as an efficient cladding to cover large areas. Because of the direct relationship between form and force distribution in tension membrane structures, form-finding procedure is an important issue. Ideally, once the optimal form is found, a uniform pre-stressing is applied to the fabric which takes the form of a minimal surface. The force density method is one of the most efficient computational form-finding techniques to solve the initial equilibrium equations. In this method, the force density ratios of the borders to the membrane is the main parameter for shape-finding. In fact, the shape is evolved and improved with the help of the stress state that is combined with the desired boundary conditions. This paper is evaluated the optimum amount of this ratio considering the curvature of the flexible boarders for structural configurations, i.e., hypar and conic membranes. Results of this study can be used (in the absence of the guidelines) for the fast and optimal design of fabric structures.

Force density ratios of flexible borders to membrane in tension fabric structures

H. Asadi,M. A. Hariri-Ardebili,M. Mirtaheri,A. P. Zandi 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.6

Architectural fabrics membranes have not only the structural performance but also act as an efficient cladding to cover large areas. Because of the direct relationship between form and force distribution in tension membrane structures, form-finding procedure is an important issue. Ideally, once the optimal form is found, a uniform pre-stressing is applied to the fabric which takes the form of a minimal surface. The force density method is one of the most efficient computational form-finding techniques to solve the initial equilibrium equations. In this method, the force density ratios of the borders to the membrane is the main parameter for shape-finding. In fact, the shape is evolved and improved with the help of the stress state that is combined with the desired boundary conditions. This paper is evaluated the optimum amount of this ratio considering the curvature of the flexible boarders for structural configurations, i.e., hypar and conic membranes. Results of this study can be used (in the absence of the guidelines) for the fast and optimal design of fabric structures.

Numerical and Experimental Behavior of Two-Story Confined Masonry Structure Subjected to Cyclic Loads

Mosaad El-Diasity,Sayed Salah,Mohamed O.R. El-Hariri,Amr A. Gamal,Tarik S. El-Salakawy 한국콘크리트학회 2024 International Journal of Concrete Structures and M Vol.18 No.1

This research presents the numerical and experimental results of lateral cyclic loading applied on a two-story confined masonry structure utilizing local materials and standards. Two half-scale confined masonry structures were constructed using clay masonry units, confining columns, tie beams, and reinforced concrete slabs. The assemblies were tested up to failure using a displacement controlled loading methodology under vertical self-weight and lateral reversed cyclic loading. The walls of the assemblies have varying perforations (solid / windows / doors) to examine the influence of perforation on in-plane and out-of-plane performance. A strengthened assembly with an exterior layer of ferrocement has been used and this suggested upgrading approach enhanced the lateral resistance of the confined assembly by about (61–95%) while improving ductility and total energy absorbed by 27%. The maximum lateral drift at failure have been decreased to (23–31%), however the corresponding load for the first visible fracture have been raised by (150–175%). Furthermore, total failure has been delayed for the strengthened walls (all sides, particularly the perforated sides). Comparing distorted forms, fracture patterns, and capacity curves of finite element models included in this research yielded excellent agreement.

A Systematic Approach for Designing Fault Tolerant Systolic Architectures

M. O. Esonu,S. Hariri,A. J. AI Khalili 대한전자공학회 1989 JTC-CSCC : Joint Technical Conference on Circuits Vol.- No.-