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Civil Engineering

Missouri University of Science and Technology

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Series

Articles 1 - 7 of 7

Full-Text Articles in Electrical and Computer Engineering

Fringe Visibility Enhanced Extrinsic Fabry-Perot Interferometer Using A Graded Index Fiber Collimator, Yinan Zhang, Yanjun Li, Tao Wei, Xinwei Lan, Ying Huang, Genda Chen, Hai Xiao May 2010

Fringe Visibility Enhanced Extrinsic Fabry-Perot Interferometer Using A Graded Index Fiber Collimator, Yinan Zhang, Yanjun Li, Tao Wei, Xinwei Lan, Ying Huang, Genda Chen, Hai Xiao

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

We report a fringe visibility-enhanced extrinsic Fabry-Perot interferometer (EFPI) by fusion splicing a quarter-pitch length of a graded-index fiber (GIF) to the lead-in single mode fiber (SMF). The performance of the GIF collimator is theoretically analyzed using a ray matrix model and experimentally verified through beam divergence angle measurements. The fringe visibility of the GIF-collimated EFPI is measured as a function of the cavity length and compared with that of a regular SMF-EFPI. At the cavity length of 500 μm, the fringe visibility of the GIF-EFPI is 0.8, while that of the SMF-EFPI is only 0.2. The visibility-enhanced GIF-EFPI may …

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Crack Detectability And Durability Of Coaxial Cable Sensors In Reinforced Concrete Bridge Applications, Genda Chen, Ryan D. Mcdaniel, Michael A. Brower, David Pommerenke Jan 2010

Crack Detectability And Durability Of Coaxial Cable Sensors In Reinforced Concrete Bridge Applications, Genda Chen, Ryan D. Mcdaniel, Michael A. Brower, David Pommerenke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The working mechanism and the measurement principle of topology-based crack sensors made of coaxial cables are briefly reviewed. The sensitivity, spatial resolution, and ruggedness of two coaxial cable sensors, respectively made of rubber and Teflon dielectric materials, were compared and validated with laboratory testing of a 4/5-scale, T-shaped, reinforced concrete beam-column specimen. Two Teflon sensors were installed on one of the solid decks of a three-span continuous highway bridge to investigate their durability and measurement repeatability. Laboratory tests indicated that both types of sensors have high sensitivity, but the Teflon sensor has a higher spatial resolution and a negligible spillover …

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A Novel Long-Period Fiber Grating Optical Sensor For Large Strain Measurement, Genda Chen, Hai Xiao, Ying Huang, Zhi Zhou, Yinan Zhang Mar 2009

A Novel Long-Period Fiber Grating Optical Sensor For Large Strain Measurement, Genda Chen, Hai Xiao, Ying Huang, Zhi Zhou, Yinan Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Critical buildings such as hospitals and police stations must remain functional immediately following a major earthquake event. Due to earthquake effects, they often experience large strains, leading to progressive collapses. Therefore, monitoring and assessing the large strain condition of critical buildings is of paramount importance to post-earthquake responses and evacuations in earthquake-prone regions. In this study, a novel large strain sensor based on the long period fiber grating (LPFG) technology is proposed and developed. CO2 laser induced LPFG sensors are characterized for such mechanical properties as strain sensitivity in extension and flexure, sensor stability, and measurement range. For practical …

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Strain Sensitive Coax Cable Sensors For Monitoring Structures, Genda Chen, James L. Drewniak, Huimin Mu, David Pommerenke Sep 2008

Strain Sensitive Coax Cable Sensors For Monitoring Structures, Genda Chen, James L. Drewniak, Huimin Mu, David Pommerenke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The invention provides increased structural monitoring systems that have sensitive continuous coaxial cable sensors. A preferred embodiment sensor cable of the invention includes an inner conductor, a dielectric jacket, and an outer conductor that is configured to passively deform responsively to strain in an associated structure. The deformation can be aided by the physical structure of the dielectric jacket, the outer conductor, or a combination of both. The deformation translates strain into a measurable change in a reflection coefficient associated with the outer conductor.

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Rubble Pile Characterization Model, William P. Schonberg, Jason Baird, Paul Nicholas Worsey, Abdeldjelil Belarbi, Roger A. Laboube, Braden Lusk, R. Flanagan, H. Burleson, Robert S. Woodley, Warren Noll Jul 2006

Rubble Pile Characterization Model, William P. Schonberg, Jason Baird, Paul Nicholas Worsey, Abdeldjelil Belarbi, Roger A. Laboube, Braden Lusk, R. Flanagan, H. Burleson, Robert S. Woodley, Warren Noll

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Rubble piles created following the collapse of a building in a combat situation can significantly impact mission accomplishment, particularly in the area of movement and maneuver. Rubble characteristics must be known, for example, in order to predict the ability of a vehicle to override the collateral damage from weapon effects in urban areas. Two types of models are developed: a first-order model and a first-principles-based model. In both models, we assume complete rubblization of the building and develop a rubble profile model using the size and composition of the collapsed structure to predict the rubble volume. In both cases, this …

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Semiempirical Electromagnetic Modeling Of Crack Detection And Sizing In Cement-Based Materials Using Near-Field Microwave Methods, Jagadish Nadakuduti, Genda Chen, R. Zoughi Apr 2006

Semiempirical Electromagnetic Modeling Of Crack Detection And Sizing In Cement-Based Materials Using Near-Field Microwave Methods, Jagadish Nadakuduti, Genda Chen, R. Zoughi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Detection and characterization of cracks in cement-based materials is an integral part of damage evaluation for health monitoring of civil structures. Microwave signals are able to penetrate inside of dielectric materials (e.g., cement-based materials) and are sensitive to local, physical, geometrical, and dielectric variations in a structure. This makes microwave nondestructive testing and evaluation (NDT&E) techniques suitable for inspection and health monitoring of civil structures. Near-field microwave NDT&E techniques offer the added advantage of providing high spatial resolution, requiring simple hardware that may be portable, low power, fast, real time, and robust. Additionally, these techniques are noncontact and one-sided. Besides …

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Novel Distributed Cable Sensors For Detection Of Cracks In Rc Structures, Genda Chen, David Pommerenke Aug 2005

Novel Distributed Cable Sensors For Detection Of Cracks In Rc Structures, Genda Chen, David Pommerenke

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this paper, the development of a fundamentally new, topology-based cable sensor design concept is summarized for crack detection in reinforced concrete (RC) structures. The sensitivity, spatial resolution, and signal loss of sensors are investigated both numerically and experimentally. Two sensors were fabricated and validated with small- and large-scale laboratory tests under different loads. Both were proven sensitive to crack of various sizes from visually undetectable to excessive, giving the location and severity of damage simultaneously. One sensor has been installed on a three-span bridge for its long-term monitoring. It is capable of recording damage that has occurred during a …

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