Dr. Claudio Nucera Profile

Dr. Claudio Nucera

Graduate Student at Univ of California San Diego

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Publications (8)

PROCEEDINGS ARTICLE | March 8, 2014

Field testing of prototype systems for the non-destructive measurement of the neutral temperature of railroad tracks

Proc. SPIE. 9061, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2014

KEYWORDS: Safety, Phase modulation, Waveguides, Sensors, Nondestructive evaluation, Ultrasonics, Head, Wave propagation, Prototyping, Temperature metrology

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PROCEEDINGS ARTICLE | April 17, 2013

Nonlinear guided waves for neutral temperature measurement in continuous welded rails: results from laboratory and field tests

Proc. SPIE. 8695, Health Monitoring of Structural and Biological Systems 2013

KEYWORDS: Liquid phase epitaxy, Waveguides, Dispersion, Ultrasonics, Head, Wave propagation, Structural health monitoring, Thermal modeling, Prototyping, Temperature metrology

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PROCEEDINGS ARTICLE | April 17, 2013

Nonlinear guided waves in solids under constrained thermal expansion

Proc. SPIE. 8695, Health Monitoring of Structural and Biological Systems 2013

KEYWORDS: Waveguides, Chemical species, Particles, Ultrasonics, Wave propagation, Transducers, Solids, Harmonic generation, Thermal modeling, Temperature metrology

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PROCEEDINGS ARTICLE | April 15, 2011

Monitoring thermal stresses and incipient buckling of continuous-welded rails: results from the UCSD/BNSF/FRA large-scale laboratory test track

Proc. SPIE. 7981, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2011

KEYWORDS: Infrared cameras, Switches, Safety, Roads, Waveguides, Ultrasonics, Head, Velocity measurements, Prototyping, Temperature metrology

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PROCEEDINGS ARTICLE | April 14, 2011

Health monitoring of prestressing tendons in post-tensioned concrete structures

Proc. SPIE. 7981, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2011

KEYWORDS: Defect detection, Waveguides, Sensors, Interfaces, Ultrasonics, Wave propagation, Signal processing, Bridges, Picosecond phenomena, Acoustic emission

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Currently 90% of bridges built in California are post-tensioned box-girder. In such structures the steel tendons are the main load-carrying components. The loss of prestress, as well as the presence of defects or the tendon breakage, can be catastrophic for the entire structure. Unfortunately, today there is no well-established method for the monitoring of prestressing (PS) tendons that can provide simultaneous information related to the presence of defects and the level of prestress in a continuous, real time manner. If such a monitoring system were available, considerable savings would be achieved in bridge maintenance since repairs would be implemented in a timely manner without traffic disruptions. This paper presents a health monitoring system for PS tendons in post-tensioned structures of interest to Caltrans. Such a system uses ultrasonic guided waves and embedded sensors to provide simultaneously and in real time, (a) measurements of the level of applied prestress, and (b) defect detection at early grow stages. The proposed PS measurement technique exploits the sensitivity of ultrasonic waves to the inter-wire contact developing in a multi-wire strand as a function of prestress level. In particular the nonlinear ultrasonic behavior of the tendon under changing levels of prestress is monitored by tracking higher-order harmonics at (nω) arising under a fundamental guided-wave excitation at (ω). Moreover this paper also present real-time damage detection and location in post-tensioned bridge joints using Acoustic Emission techniques. Experimental tests on large-scale single-tendon PT joint specimens, subjected to multiple load cycles, will be presented to validate the monitoring of PS loads (through nonlinear ultrasonic probing) and the monitoring of damage progression and location (through acoustic emission techniques). Issues and potential for the use of such techniques to monitor post-tensioned bridges in the field will be discussed.

PROCEEDINGS ARTICLE | April 14, 2011

UCSD/FRA non-contact ultrasonic guided-wave system for rail inspection: an update

Proc. SPIE. 7981, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2011

KEYWORDS: Safety, Statistical analysis, Defect detection, Waveguides, Reliability, Inspection, Ultrasonics, Head, Molybdenum, Prototyping

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PROCEEDINGS ARTICLE | April 13, 2011

Nonlinear ultrasonic guided waves for prestress level monitoring in prestressing strands for post-tensioned concrete structures

Proc. SPIE. 7981, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2011

KEYWORDS: Waveguides, Interfaces, 3D modeling, Ultrasonics, Wave propagation, Transducers, Finite element methods, Bridges, Chemical elements, Signal detection

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PROCEEDINGS ARTICLE | March 30, 2009

Nonlinear ultrasonic guided waves for stress monitoring in prestressing tendons for post-tensioned concrete structures

Proc. SPIE. 7292, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2009

KEYWORDS: Defect detection, Waveguides, Sensors, Interfaces, Ultrasonics, Wave propagation, Transducers, Bridges, Picosecond phenomena, Signal detection

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Showing 5 of 8 publications

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