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CORRELATION OF ACOUSTIC EMISSION PARAMETERS WITH WEIGHT AND VELOCITY OF MOVING VEHICLES
Title
CORRELATION OF ACOUSTIC EMISSION PARAMETERS WITH WEIGHT AND VELOCITY OF MOVING VEHICLES.
Creator
Kolgaonkar, Amar, Moslehy, Faissal, University of Central Florida
Abstract / Description
The thesis is motivated by the goal of doing initial investigation and experimentation for the development of Weigh-in-Motion (WIM) system using acoustic emission phenomenon. A great deal of research is going on for measuring the weight of moving vehicles. Weigh-in-motion of commercial vehicles is essential for management of freight traffic, highway infrastructure design and maintenance, and monitoring of heavy weight vehicles. The research work presents a methodology for correlating the...
Show moreThe thesis is motivated by the goal of doing initial investigation and experimentation for the development of Weigh-in-Motion (WIM) system using acoustic emission phenomenon. A great deal of research is going on for measuring the weight of moving vehicles. Weigh-in-motion of commercial vehicles is essential for management of freight traffic, highway infrastructure design and maintenance, and monitoring of heavy weight vehicles. The research work presents a methodology for correlating the weight of a moving vehicle with acoustic emission parameters (such as counts and energy). Furthermore, the correlation between the speed of vehicle with the acoustic emission parameters is developed. Preliminary analysis and experimentations were conducted for the study of propagation of acoustic signals in plate like structure and effect of dynamic loadings on Kaiser Effect. Initial testing revealed that there is a linear correlation between the impact force and the acoustic emission parameters. Also a polynomial regression of second order was found between the speed of vehicle and acoustic emission parameters. Road testing was conducted to investigate the correlation between weight of the vehicle and acoustic emission parameters. A linear relation was found between the weight of vehicle and acoustic emission parameters represented by counts, signal energy and absolute energy.
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Date Issued
2005
Identifier
CFE0000490, ucf:46354
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0000490
NONDESTRUCTIVE TESTING METHODS AIDED VIA NUMERICAL COMPUTATION MODELS FOR VARIOUS CRITICAL AEROSPACE AND POWER GENERATION SYSTEMS
Title
NONDESTRUCTIVE TESTING METHODS AIDED VIA NUMERICAL COMPUTATION MODELS FOR VARIOUS CRITICAL AEROSPACE AND POWER GENERATION SYSTEMS.
Creator
Warren, Peter, Ghosh, Ranajay, Raghavan, Seetha, Gou, Jihua, University of Central Florida
Abstract / Description
A current critical necessity for all industries which utilize various equipment that operates in hightemperature and extreme environments, is the ability to collect and analyze data via non destructivetesting (NDT) methods. Operational conditions and material health must be constantly monitoredif components are to be implemented precisely to increase the overall performance and efficiencyof the process. Currently in both aerospace and power generation systems there are many methodsthat are...
Show moreA current critical necessity for all industries which utilize various equipment that operates in hightemperature and extreme environments, is the ability to collect and analyze data via non destructivetesting (NDT) methods. Operational conditions and material health must be constantly monitoredif components are to be implemented precisely to increase the overall performance and efficiencyof the process. Currently in both aerospace and power generation systems there are many methodsthat are being employed to gather several necessary properties and parameters of a given system.This work will focus primarly on two of these NDT methods, with the ultimate goal of contributingto not only the method itself, but also the role of numerical computation to increase the resolutionof a given technique. Numerical computation can attribute knowledge onto the governing mechanicsof these NDT methods, many of which are currently being utilized in industry. An increase inthe accuracy of the data gathered from NDT methods will ultimately lead to an increase in operationalefficiency of a given system.The first method to be analyzed is a non destructive emmision technique widely referred to asaccoustic ultrasonic thermography. This work will investigate the mechanism of heat generationin acoustic thermography using a combination of numerical computational analysis and physicalexperimentation. Many of the challenges typical of this type of system are addressed in this work.The principal challenges among them are crack detection threshold, signature quality and the effectof defect interactions. Experiments and finite element based numerical simulations are employed,in order to evaluate the proposed method, as well as draw conclusions on the viability for futureextension and integration with other digital technologies for health monitoring. A method to determinethe magnitude of the different sources of heat generation during an acoustic excitation isalso achieved in this work. Defects formed through industrial operation as well as defects formedthrough artificial manufacturing methods were analyzed and compared.The second method is a photoluminescence piezospectroscopic (PLPS) for composite materials.The composite studied in this work has one host material which does not illuminate or have photoluminescenceproperties, the second material provides the luminescence properties, as well asadditional overall strength to the composite material. Understanding load transfer between the reinforcementsand matrix materials that constitute these composites hold the key to elucidating theirmechanical properties and consequent behavior in operation. Finite element simulations of loadingeffects on representative embedded alumina particles in a matrix were investigated and comparedwith experimental results. The alumina particles were doped with chromium in order to achieveluminscence capability, and therefore take advantage of the piezospectrscopic measurement technique.Mechanical loading effects on alumina nanoparticle composites can be captured with Photostimulated luminescent spectroscopy, where spectral shifts from the particles are monitored withload. The resulting piezospectroscopic (PS) coefficients are then used to calculate load transferbetween the matrix and particle. The results from the simulation and experiments are shown tobe in general agreement of increase in load transferred with increasing particle volume fractiondue to contact stresses that are dominant at these higher volume fractions. Results from this workpresent a combination of analytical and experimental insight into the effect of particle volume fractionon load transfer in ceramic composites that can serve to determine properties and eventuallyoptimize various parameters such as particle shape, size and dispersion that govern the design ofthese composites prior to manufacture and testing.
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Date Issued
2018
Identifier
CFE0007262, ucf:52203
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007262
DEVELOPMENT OF A WEIGH-IN-MOTION SYSTEM USING ACOUSTIC EMISSION SENSORS
Title
DEVELOPMENT OF A WEIGH-IN-MOTION SYSTEM USING ACOUSTIC EMISSION SENSORS.
Creator
Bowie, Jeanne, Radwan, Essam, University of Central Florida
Abstract / Description
This dissertation proposes a system for weighing commercial vehicles in motion using acoustic emission sensors attached to a metal bar placed across the roadway. The signal from the sensors is analyzed by a computer and the vehicle weight is determined by a statistical model which correlates the acoustic emission parameters to the vehicle weight. Such a system would be portable and low-cost, allowing for the measurement of vehicle weights in much the same way commercial tube and radar...
Show moreThis dissertation proposes a system for weighing commercial vehicles in motion using acoustic emission sensors attached to a metal bar placed across the roadway. The signal from the sensors is analyzed by a computer and the vehicle weight is determined by a statistical model which correlates the acoustic emission parameters to the vehicle weight. Such a system would be portable and low-cost, allowing for the measurement of vehicle weights in much the same way commercial tube and radar counters routinely collect vehicle speed and count. The system could be used to collect vehicle speed and count data as well as weight information. Acoustic emissions are naturally occurring elastic waves produced by the rapid release of energy within a material. They are caused by deformation or fracturing of a solid due to thermal or mechanical stress. Acoustic emission sensors have been developed to detect these waves and computer software and hardware have been developed to analyze and provide information about the waveforms. Acoustic emission testing is a common form of nondestructive testing and is used for pressure vessel testing, leak detection, machinery monitoring, structural integrity monitoring, and weld monitoring, among other things (Miller, 1987). For this dissertation, acoustic emission parameters were correlated to the load placed on the metal test bar to determine the feasibility of using a metal test bar to measure the weight of a vehicle in motion. Several experiments were done. First, the concept was tested in a laboratory setting using an experimental apparatus. A concrete cylinder was mounted on a frame and rotated using a motor. The metal test bar was applied directly to the surface of the cylinder and acoustic emission sensors were attached to each end of the bar. As the cylinder rotated, a motorcycle tire was pushed up against the cylinder using a scissor jack to simulate different loads. The acoustic emission response in the metal test strip to the motorcycle tire rolling over it was detected by the acoustic emission sensors and analyzed by the computer. Initial examinations of the data showed a correlation between the force of the tire against the cylinder and the energy and count of the acoustic emissions. Subsequent field experiments were performed at a weigh station on I-95 in Flagler County, Florida. The proposed weigh-in-motion system (the metal test bar with attached acoustic emission sensors) was installed just downstream of the existing weigh-in-motion scale at the weigh station. Commercial vehicles were weighed on the weigh station weigh-in-motion scale and acoustic emission data was collected by the experimental system. Test data was collected over several hours on two different days, one in July 2008 and the other in April 2009. Initial examination of the data did not show direct correlation between any acoustic emission parameter and vehicle weight. As a result, a more sophisticated model was developed. Dimensional analysis was used to examine possible relationships between the acoustic emission parameters and the vehicle weight. In dimensional analysis, a dimensionally correct equation is formed using measurable parameters of a system. The dimensionally correct equation can then be tested using experimental data. Dimensional analysis revealed the possible relationships between the acoustic emission parameters and the vehicle weight. Statistical models for weight using the laboratory data and using the field data were developed. Dimensional analysis variables as well as other relevant measurable parameters were used in the development of the statistical models. The model created for the April 2009 dataset was validated, with only 27 lbs average error in the weight calculation as compared with the weight measurement made with the weigh station weigh-in-motion scale. The maximum percent error for the weight calculation was 204%, with about 65% of the data falling within 30% error. Additional research will be needed to develop an acoustic emission weigh-in-motion system with adequate accuracy for a commercial product. Nevertheless, this dissertation presents a valuable contribution to the effort of developing a low-cost acoustic emission weigh-in-motion scale. Future research needs that were identified as part of this dissertation include: • Examination of the effects of pavement type (flexible or rigid), vehicle speeds greater than 50 mph, and temperature • Determination of the best acoustic emission sensor for this system • Exploration of the best method to separate the data from axles which pass over the equipment close together in time (such as tandem axles) • Exploration of the effect of repeated measures on improving the accuracy of the system.
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Date Issued
2011
Identifier
CFE0003581, ucf:48903
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003581
The Consequences of a Reduced Superlattice Thickness on Quantum Cascade LASER Performance
Title
The Consequences of a Reduced Superlattice Thickness on Quantum Cascade LASER Performance.
Creator
Figueiredo, Pedro, Lyakh, Arkadiy, Peale, Robert, Klemm, Richard, Fathpour, Sasan, University of Central Florida
Abstract / Description
Coherent infrared radiation sources are essential for the operability of a wide range of scientific, industrial, military and commercial systems. The importance of the mid-infrared spectral region cannot be understated. Numerous molecules have some vibrational band in this range, allowing for identification of species by means of absorption, emission or some other form of spectroscopy. As such, spectroscopy alone has numerous applications ranging from industrial process control to disease...
Show moreCoherent infrared radiation sources are essential for the operability of a wide range of scientific, industrial, military and commercial systems. The importance of the mid-infrared spectral region cannot be understated. Numerous molecules have some vibrational band in this range, allowing for identification of species by means of absorption, emission or some other form of spectroscopy. As such, spectroscopy alone has numerous applications ranging from industrial process control to disease diagnosis utilizing breath analysis. However, despite the discovery of the LASER in the 60s, to this day the amount of coherent sources in this range is limited. It is for this reason that the quantum cascade laser has gained such momentum over the past 23 years.Quantum Cascade LASERS (QCL) are semiconductor LASERS which are based on the principle of bandgap engineering. This incredible technique is a testament to the technological maturity of the semiconductor industry. It has been demonstrated that by having precise control of individual material composition (band gap control), thicknesses on the order of monolayers, and doping levels for each individual layer in a superlattice, we have unprecedented flexibility in designing a LASER or detector in the infrared. And although the technology has matured since it's discovery, there still remain fundamental limitations on device performance. In particular, active region overheating limits QCL performance in a high duty cycle mode of operation.In this dissertation, along with general discussion on the background of the QCL, we propose a solution of where by limiting the growth of the superlattice to a fraction of typical devices, we allow for reduction of the average superlattice temperature under full operational conditions. The consequences of this reduction are explored in theory, experiment and system level applications.
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Date Issued
2017
Identifier
CFE0006592, ucf:51273
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0006592