Browsing by Author "Aktan, HM"

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item: Conference-Full-text
Clustering Techniques and Artificial Neural Network for Acoustic Emission Data Analysis
(2015-12-29) Attanayake, UB; Aktan, HM; Mejia, J; Hay, R
Abstract: Acoustic emission (AE) sensor technology is commonly used for real-time monitoring of fatigue sensitive details. This is mainly due to its ability to detect fatigue events (crack initiation and opening) by mounting sensors in the vicinity of potential crack location. Also, AE data can be used for damage location detection. Even though AE provides many capabilities with regard to fatigue monitoring, many implementation challenges exist. A majority of the challenges is associated with noise elimination, AE signal analysis, and interpretation of the results. This article describes AE implementation for monitoring a fatigue-sensitive detail and use of data analysis techniques such as cluster analysis, non-linear mapping (NLM), and three-class classifiers to identify the relationship of each cluster to the characteristics of crack opening signals, background noise, and structural resonance.
item: Article-Full-text
Clustering Techniques and Artificial Neural Network for Acoustic Emission Data Analysis
(2015-12-29) Attanayake, UB; Aktan, HM; Mejia, J; Hay, R
Acoustic emission (AE) sensor technology is commonly used for real-time monitoring of fatigue sensitive details. This is mainly due to its ability to detect fatigue events (crack initiation and opening) by mounting sensors in the vicinity of potential crack location. Also, AE data can be used for damage location detection. Even though AE provides many capabilities with regard to fatigue monitoring, many implementation challenges exist. A majority of the challenges is associated with noise elimination, AE signal analysis, and interpretation of the results. This article describes AE implementation for monitoring a fatigue-sensitive detail and use of data analysis techniques such as cluster analysis, non-linear mapping (NLM), and three-class classifiers to identify the relationship of each cluster to the characteristics of crack opening signals, background noise, and structural resonance.
item: Conference-Abstract
Decision making framework for transportation infrastructure selection
(Department of Civil Engineering, 2011-07) Attanayake, U; Mohammed, AW; Hu, Y; Abudayyeh, O; Aktan, HM; Pasindu, HR
The world transportation system matures day-by-day wherein the congestion growth rate is alarming while its infrastructure growth has slowed down, which affects the quality of life. Developing highway infrastructure by utilizing modern technology and knowledge is vital for successful completion of the projects with least impact to traffic and local economy. Accelerated construction technology is developed to minimize construction duration; hence, to mitigate congestion, reduce on-site environmental impacts, and to improve the safety of stakeholders. Selection of construction methods and technology is based on available funding, proposals from contractors or design-bid-build contracts that lack many of the factors which should tangibly control the decision of type of facility to be constructed. The decision group comprising of representatives of owner agency and contractor with differing preferences, experiences and background requires a framework to negotiate among them to arrive at an optimal decision for a particular project. The available decision making frameworks include several simple "Yes"/ "No" answer questions that do not consider relative importance among the factors providing a transparent methodology or a tool to arrive at the decision. In addition, potential constraints are not addressed to identify structural systems/configurations with respect to their performance and construction techniques/technologies for implementation at specific sites. A multicriteria decision making framework is presented in this paper using highway bridge construction as an example. The framework is developed using Analytical Hierarchy Process (AHP) and accommodates many quantitative and qualitative factors identified through interviews and review of literature including post-construction and lessons learned reports.
item: Conference-Full-text
Temporary Substructure Forces during Bridge Slide: Impact of Sliding Friction and Substructure Alignment
(2016-01-05) Ridvanoglu, OU; Attanayake, UB; Aktan, HM
Slide-in Bridge Construction (SIBC) is different from the conventional bridge construction because of the activity required to move the bridge to final position following construction. Moving activity requires bridge to be on a temporary support structure, resting on a sliding system such as bearings suitable for sliding, and a system of force actuation for pushing or pulling the bridge. Two SIBC projects were recently completed in Michigan, USA. SIBC being new to the bridge community, substructure forces that are developed during slides are best estimated. Hence, one of the Michigan projects was selected and slide operation was simulated using dynamic explicit finite element analysis techniques. This article presents use of dynamic explicit finite element analysis for evaluating temporary substructure forces during bridge slide. Further the analysis results are used to explain the impact of unequal friction at sliding surfaces and differential alignment of the temporary supports on substructure forces and bridge superstructure movement. Typically, bridge superstructures are slid in place using forcecontrolled systems. Analysis was performed using force-controlled and displacement-controlled methods. Then, the analysis results are used to explain the benefits of using displacement-controlled methods with force monitoring to slide a bridge rather than employing a force-controlled method.