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health-monitoring
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Damage detection in an offshore jacket platform using genetic algorithm based finite element model updating with noisy modal data
, Article Procedia Engineering, Solo, Jawa Tengah ; Volume 54 , March , 2013 , Pages 480-490 ; 18777058 (ISSN); 9781627486354 (ISBN) ; Golafshani, A. A ; Sharif University of Technology
2013
Abstract
Offshore jacket platforms are one of the most motivating structures for damage detection due to their importance and productivity. In this study, the application of finite element model updating in damage detection of an offshore jacket platform is investigated. The objective function of this method is based on the measured and analytical modal data, including natural frequencies and mode shapes. However, the measured data is expected to be noisy. Also, to avoid obtaining false damage results, a penalty term is added to the objective function. To update the model, genetic algorithm is utilized as a robust global searching tool. Afterward, the efficiency of this method is evaluated on several...
Seesaw scenarios of lockdown for COVID-19 pandemic: Simulation and failure analysis
, Article Sustainable Cities and Society ; Volume 73 , 2021 ; 22106707 (ISSN) ; Akhavan Niaki, S. T ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The ongoing COVOD-19(SARS-CoV-2) outbreak has had a devastating impact on the economy, education and businesses. In this paper, the behavior of an epidemic is simulated on different contact networks. Herein, it is assumed that the infection may be transmitted at each contact from an infected person to a susceptible individual with a given probability. The probability of transmitting the disease may change due to the individuals' social behavior or interventions prescribed by the authorities. We utilized simulation on the contact networks to demonstrate how seesaw scenarios of lockdown can curb infection and level the pandemic without maximum pressure on the poor societies. Soft scenarios...
Seesaw scenarios of lockdown for COVID-19 pandemic: Simulation and failure analysis
, Article Sustainable Cities and Society ; Volume 73 , 2021 ; 22106707 (ISSN) ; Akhavan Niaki, S. T ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The ongoing COVOD-19(SARS-CoV-2) outbreak has had a devastating impact on the economy, education and businesses. In this paper, the behavior of an epidemic is simulated on different contact networks. Herein, it is assumed that the infection may be transmitted at each contact from an infected person to a susceptible individual with a given probability. The probability of transmitting the disease may change due to the individuals' social behavior or interventions prescribed by the authorities. We utilized simulation on the contact networks to demonstrate how seesaw scenarios of lockdown can curb infection and level the pandemic without maximum pressure on the poor societies. Soft scenarios...
Data Analysis for Damage Detection Using Machine Learning Algorithms
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
The pressurized structure such as aircraft fuselage and pipeline (in the oil and water transportation) have a great importance in today’s world. There is a growing tendency in improving design factors, safety and maintenance of such valuable structures. Change of design’s philosophy during the time from infinite life to safe damage and safe life and after that damage tolerance, are a process leading to many changes in design and consequently the methods of inspection, evaluation and maintenance. In this way, using old methods like non-destructive test and evaluation (NDT/E) is encountered with different problems when damage is tiny and there is no coincidence in examination (inspection)...
Pedal: Power-delay product objective function for internet of things applications
, Article 34th Annual ACM Symposium on Applied Computing, SAC 2019, 8 April 2019 through 12 April 2019 ; Volume Part F147772 , 2019 , Pages 892-895 ; 9781450359337 (ISBN) ; Mohammad Salehi, A. A ; Shirbeigi, M ; Hosseini Monazzah, A. M ; Ejlali, A ; ACM Special Interested Group on Applied Computing ; Sharif University of Technology
Association for Computing Machinery
2019
Abstract
The increasing trend in the number of smart connected devices has turned the routing procedure as one of the major challenges in IoT infrastructures. The Routing Protocol for Low Power and Lossy Networks (RPL) was introduced to satisfy different IoT application requirements through Objective Functions (OF). Although there have been several studies on introducing new OFs in order to fulfill specific IoT characteristics, e.g., energy and delay efficiency, reliability, and stability, but still there is a lack of novel OFs which fulfill the IoT application requirements in terms of both, the performance and the power consumption simultaneously. In this paper, we have proposed PEDAL, an OF which...
Pedal: Power-delay product objective function for internet of things applications
, Article 34th Annual ACM Symposium on Applied Computing, SAC 2019, 8 April 2019 through 12 April 2019 ; Volume Part F147772 , 2019 , Pages 892-895 ; 9781450359337 (ISBN) ; Mohammad Salehi, A. A ; Shirbeigi, M ; Hosseini Monazzah, A. M ; Ejlali, A ; ACM Special Interested Group on Applied Computing ; Sharif University of Technology
Association for Computing Machinery
2019
Abstract
The increasing trend in the number of smart connected devices has turned the routing procedure as one of the major challenges in IoT infrastructures. The Routing Protocol for Low Power and Lossy Networks (RPL) was introduced to satisfy different IoT application requirements through Objective Functions (OF). Although there have been several studies on introducing new OFs in order to fulfill specific IoT characteristics, e.g., energy and delay efficiency, reliability, and stability, but still there is a lack of novel OFs which fulfill the IoT application requirements in terms of both, the performance and the power consumption simultaneously. In this paper, we have proposed PEDAL, an OF which...
Evaluation of the sparse reconstruction and the delay-and-sum damage imaging methods for structural health monitoring under different environmental and operational conditions
, Article Measurement: Journal of the International Measurement Confederation ; Volume 169 , 2021 ; 02632241 (ISSN) ; Navazi, H. M ; Groves, R. M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In this paper, the performance of the sparse reconstruction (SR) and the delay-and-sun (DAS) methods for damage localization, were evaluated for various environmental and operational conditions, both numerically and experimentally. To assess these damage localization methods, a methodology based on the Taguchi method was used to make the experimental design, and a modified performance-index was defined to represent the quality of reconstructed images. Then, the robustness and the accuracy of each method, in a well-defined performance region relevant to in-service aerospace structures, were investigated using the Taguchi and analysis of variance methods. It was concluded that for the defined...
Study of Pattern of Sensor Installation for Analysis of Offshore Jacket Behavior
, M.Sc. Thesis Sharif University of Technology ; Golafshani, Ali Akbar (Supervisor)
Abstract
Nowadays, many offshore jacket platforms have been built in all over the world for excavating oil and gas. Due to cost of construction and maintenance, they are considered as national assets. Jacket platforms are always under various types of loads in their time life, so they cause some damages to them. Hence, on time damage detection can prevent possible extravagant costs of repair and reconstruction. Because many jacket platforms are in Iran, this issue can be very important.Structural health monitoring (SHM) improvised to ensure safety and detect damages of structures uses sensors. They transfer data received from structures to the computers in order that after interpretation of data,...
Adaptive Lossless Image Compression of Pipelines in Smart Structures
, M.Sc. Thesis Sharif University of Technology ; Mortazavi, Mohammad (Supervisor) ; Ghorshi, Mohammad Ali (Supervisor)
Abstract
Structural Health Monitoring (SHM) means to give a diagnosis of the “state” of the subjects. Small leaks along the entire lengths of oil pipelines are detected and located by monitoring.Nowadays health monitoring of pipeline in water, gas, oil and chemical industry has been the focus of researchers. This is due to the fact that leak accidents may cause great economic problems to human resources as well as extreme environmental pollution. This project focuses on a visual and photographic observation system as leakage detection to monitor long range pipelines. In this system, several cameras with overlapping views are located along the entire lengths of pipelines. We are using digital cameras...
Damage detection of offshore jacket structures using frequency domain selective measurements
, Article Journal of Marine Science and Application ; Volume 12, Issue 2 , June , 2013 , Pages 193-199 ; 16719433 (ISSN) ; Golafshani, A. A ; Ghodrati, E ; Sharif University of Technology
2013
Abstract
The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural healthCgreater detection efficiency. In addition, the performance of the proposed method was evaluated in relation to multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform, and the results proved to be satisfactory utilizing the proposed methodology
Health monitoring of structures using few frequency response measurements
, Article Scientia Iranica ; Volume 17, Issue 6 A , NOVEMBER-DECEMBER , 2010 , Pages 493-500 ; 10263098 (ISSN) ; Kianian, M ; Ghodrati, E ; Sharif University of Technology
2010
Abstract
The development of damage detection techniques for offshore jacket structures is vital for preventing catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitoring. In this approach, the concept of a minimum rank perturbation theory is used. The feasibility of using a finite number of sensors and its effect on damage detection capabilities is investigated. In addition, the performance of the proposed method is evaluated in the case of multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform
High performance grout connection for pre-cast concrete structures
, Article International Conference on Sustainable Construction Materials and Technologies, Coventry, 11 June 2007 through 13 June 2007 ; 2007 , Pages 479-485 ; 9780415446891 (ISBN) ; Sharif University of Technology
2007
Abstract
Connections have very important role in pre-cast concrete structures, especially in seismic zones, and grout connections increase strength and resistance of pre-cast concrete structures for lateral forces. High performance grout connections (HPGC) provide new opportunities to design cost-effective pre-cast concrete structures. HPGC have been proposed to decrease cost of insulation, erection and crane cost of pre-cast concrete structures and to overcome weakness of traditional pre-cast concrete structure connections .This research focuses on properties of grout materials properties which produced in Iran and the effect of propylene fiber on the performance of grout connection. In the first...
Efficient health monitoring of buildings using failure modes and effects analysis case study: Air handling unit system
, Article Journal of Building Engineering ; Volume 29 , 2020 ; Aramoun, F ; Saboohi, Y ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
System health management based on condition monitoring is of great value and significance for improving system performance and reliability. As more data from condition monitoring is obtained, the efficiency of system health monitoring improves. However, increasing the amount of data by installing new sensors on system components is restricted by a variety of factors such as budget, weight and space allowance. Therefore, sensor selection in the most optimal manner in order to achieve maximum valuable information from system is an important issue. In this study, a novel concept is introduced that can be used in sensor combination optimization problems. This concept employs failure modes and...
Crack Propagation Monitoring of Gas Turbine Blades Using Modal Analysis
, M.Sc. Thesis Sharif University of Technology ; Zabihollah, Abolghasem (Supervisor) ; Behzad, Mehdi (Co-Advisor)
Abstract
Rotary equipment are being used in many industries over a wide range of applications, such as gas turbine. Due to the nature of the operating conditions, gas turbines are subjected to variety of damages especially crack propagation of a blade. The Cracks propagation may lead to catastrophic failure during operation. Therefore, detection of the crack presence and its propagation is very important and may reduce possible significant cost of the whole system failure. The thesis aims to investigate the cracks presence and their propagation effects on vibration of a turbine blade which is located at the National Iranian South Oilfields. First, theoretical study is calculated to validate an...
Identification of Damage Type and Location in Reinforced Concrete Piers of Slab– Beam Bridges Using Numerical Methods
, M.Sc. Thesis Sharif University of Technology ; Ahmadizadeh, Mahdi (Supervisor)
Abstract
Bridges are among the crucial elements of transportation networks, and play an important role in facilitating emergency relief efforts following earthquakes. For this reason, it is emparative to monitor their damages to ensure about their performace in earthquakes. The structure of a bridge is divided into two parts, namely the superstructure and substructure. Due to the relatively high rigidity and strength of superstructures, most of structural damage is usually concentrated in substructures, which may ultimately affect the overall stability of the bridge. Therefore, assessing the level of damage in the substructure is of utmost concern. This research attempts to evaluate the damage in the...
Using Bayesian Approach in Life Management of a Monitored Structural System
, M.Sc. Thesis Sharif University of Technology ; Adibnazari, Saeed (Supervisor)
Abstract
In presence of epistemic and aleatoric uncertainties of the structural systems, it is better to investigate the events in probabilistic manner. Bayesian inference is an approach that can update the current knowledge of probabilities with new evidence. The main objective of this study was evaluating the advanteges of using Bayesian approach in two main area of structural health monitoring, model calibration and decision making. In each of these two areas, one case study was conducted. First case study was prediction of crack growth life in a pre-cracked aluminum plate and the results showed that using Bayesian approach in calibration of crack growth model and measurement model of health...
Numerical Simulation of Acoustic Emission Waves for Structural Health Monitoring
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Sayyaadi, Hassan (Supervisor)
Abstract
The aim in the current thesis is to introduce a powerful method based on quantitative Acoustic Emission approach for structures health monitoring in a way that the proposed method can be used for industrial purposes. In order to do this, after presenting a survey on moment tensor concept and its relation to crack nucleation in solids, the equivalent forces of crack initiation are calculated. These forces are then applied on the meshed area of a 2D finite element model. The corresponding result is the propagation of acoustic waves which are modeled by using finite element analysis. After waveform data acquisition in the imaginary sensor positions and implying source location analysis, the...
Laser-Based Inspection of Internal Geometry of Industrial Pipes in Pigging Procedure
, M.Sc. Thesis Sharif University of Technology ; Khodaygan, Saeed (Supervisor)
Abstract
Along with improvement of technology and need for access to energy resources, existence of pipelines such as gas, oil and water pipes is vital for our lives. These pipes will be eroded and damaged over time. With the prediction of the defects and tracking of pipeline paths, the probability of sudden damages is greatly reduced. In this research, at first various non-destructive methods of monitoring the pipelines are investigated and it is shown that the laser method is the most comprehensive and non-destructive inspection method and then the background of the chosen method is examined. Also, the hardware aspect of the system and the proper layout of the laser sensors are determined on the...
Structural Health Monitoring and Damage Detection of Pipelines
, M.Sc. Thesis Sharif University of Technology ; Haj Sadeghi, Khosro (Supervisor)
Abstract
Pipelines are the preferred means for transporting of liquid or gas phase materials. The economy of many countries is extremely dependent upon a large network of pipelines systems to transport and distribute the nation’s energy resources. Damages to the pipe structure may cause leakage and result in economic losses or even loss of life. Developing methods for detecting the anomalies and damages to the structure before they lead to catastrophic events is vital. Multiple pipeline misadventures over the past several years have resulted in hundreds of fatalities and billions of dollars in property damages. These accidents demonstrate that the current monitoring methods are not sufficient...
Structural Health Monitoring of Buried Pipelines Using Piezoelectric Sensor
, M.Sc. Thesis Sharif University of Technology ; Zabihollah, Abolghasem (Supervisor)
Abstract
Large-size buried pipelines are an efficient way of transporting of water, waste water, sewage, gas, and oil resources in across the world. Since the buried pipe lines are exposed to many unexpected conditions, such as landslides, corrosion, fatigue, unexpected loading, earthquakes, material flaws or even intentional damaging, so the inspection requirements lead to adoption of new method of maintenance, protection and conserving of pipelines. This proposed project aims to improve the trustworthiness, reliable, yet economical technologies for monitoring of behavior of buried pipe lines during operation and assessing the risk of pipe lines failure. Piezoelectric sensor is bonded on the surface...