The application of interferometric techniques to the nondestructive inspection of fiber-reinforced materials

Nokes, J. P.; Cloud, Gary

doi:10.1007/bf02322147

Cited by 42 publications

(25 citation statements)

References 7 publications

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“…For a given method to be sensitive to incipient damage, the wavelength of the excitation must be smaller than the characteristic length of the damage to be detected (Stokes and Cloud, 1993). Because the impedance method implements such high frequency ranges when compared to traditional vibrations, the electrical impedance of an MFC is much more sensitive to incipient damage.…”

Section: Testing Parameters Involved With Impedance Methodsmentioning

confidence: 99%

Pipeline Structural Health Monitoring Using Macro-fiber Composite Active Sensors

Thien

2006

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The United States economy is heavily dependent upon a vast network of pipeline systems to transport and distribute the nation's energy resources. As this network of pipelines continues to age, monitoring and maintaining its structural integrity remains essential to the nation's energy interests. Numerous pipeline accidents over the past several years have resulted in hundreds of fatalities and billions of dollars in property damages. These accidents show that the current monitoring methods are not sufficient and leave a considerable margin for improvement. To avoid such catastrophes, more thorough methods are needed.As a solution, the research of this thesis proposes a structural health monitoring (SHM) system for pipeline networks. By implementing a SHM system with pipelines, their structural integrity can be continuously monitored, reducing the overall risks and costs associated with current methods. The proposed SHM system relies upon the deployment of macro-fiber composite (MFC) patches for the sensor array. Because MFC patches are flexible and resilient, they can be permanently mounted to the curved surface of a pipeline's main body. From this location, the MFC patches are used to monitor the structural integrity of the entire pipeline.Two damage detection techniques, guided wave and impedance methods, were implemented as part of the proposed SHM system. However, both techniques utilize the same MFC patches. This dual use of the MFC patches enables the proposed SHM system to require only a single sensor array. The presented Lamb wave methods demonstrated the ability to correctly identify and locate the presence of damage in the main body of the pipeline system, including simulated cracks and actual corrosion damage. The presented impedance methods demonstrated the ability to correctly identify and locate the presence of damage in the flanged joints of the pipeline system, including the loosening of bolts on the flanges. In addition to damage to the actual pipeline itself, the proposed methods were used to demonstrate the capability of detecting deposits inside of pipelines. Monitoring these deposits can prevent clogging and other hazardous situations.Finally, suggestions are made regarding future research issues which are needed to advance this research. Because the research of this thesis has only demonstrated the feasibility of the techniques for such a SHM system, these issues require attention before any commercial applications can be realized.

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Section: Testing Parameters Involved With Impedance Methodsmentioning

confidence: 99%

Pipeline Structural Health Monitoring Using Macro-fiber Composite Active Sensors

Thien

2006

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“…The range for a given structure is determined by a trial-and-error method. To sense incipienttype damage which does not result in any measurable change in the structure's global sti ness properties, it is necessary for the wavelength of excitation to be smaller than the characteristic length of the damage to be detected [17]. There has been little analytical work done about the vibration modes of complex structures at these ultrasonic frequencies, however.…”

Section: Analysis Of a Pipeline Structure With Bolted Jointsmentioning

confidence: 99%

Feasibility of using impedance‐based damage assessment for pipeline structures

Park

Cudney

Inman

2001

Earthq Engng Struct Dyn

248

130

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SUMMARYThis paper presents the feasibility of using an impedance-based health monitoring technique in monitoring a critical civil facility. The objective of this research is to utilize the capability of the impedance method in identifying structural damage in those areas where a very quick condition monitoring is urgently needed, such as in a post-earthquake analysis of a pipeline system. The basic principle behind this technique is to utilize high-frequency structural excitation (typically greater than 30 kHz) through surface-bonded piezoelectric sensors=actuators to detect changes in structural point impedance due to the presence of damage. Real-time damage detection in pipes connected by bolted joints was investigated, and the capability of the impedance method in tracking and monitoring the integrity of the typical civil facility has been demonstrated. Data collected from the tests illustrates the capability of this technology to detect imminent damage under normal operating conditions and immediately after a natural disaster.

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“…shown that the wavelength of the signal, used to detect damage of a given size, needs to be smaller than the characteristic length of the damage [15]. To satisfy this requirement and to be able to detect incipient damage, the frequency range of 30-400 kHz is usually used [8].…”

Section: Impedance-based Structural Health Monitoringmentioning

confidence: 99%

Development and Integration of Hardware and Software for Active-Sensors in Structural Monitoring

Overly

2007

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Structural Health Monitoring (SHM) promises to deliver great benefits to many industries.Primarily among them is a potential for large cost savings in maintenance of complex structures such as aircraft and civil infrastructure. However, several large obstacles remain before widespread use on structures can be accomplished. The development of three components would address many of these obstacles: a robust sensor validation procedure, a low-cost active-sensing hardware and an integrated software package for transition to field deployment. The research performed in this thesis directly addresses these three needs and facilitates the adoption of SHM on a larger scale, particularly in the realm of SHM based on piezoelectric (PZT) materials.The first obstacle addressed in this thesis is the validation of the SHM sensor network.PZT materials are used for sensor/actuators because of their unique properties, but their functionality also needs to be validated for meaningful measurements to be recorded. To allow for a robust sensor validation algorithm, the effect of temperature change on sensor diagnostics and the effect of sensor failure on SHM measurements were classified. This classification allowed for the development of a sensor diagnostic algorithm that is temperature invariant and can indicate the amount and type of sensor failure.Secondly, the absence of a suitable commercially-available active-sensing measurement node is addressed in this thesis. A node is a small compact measurement device used iv ABSTRACT in a complete system. Many measurement nodes exist for conventional passive sensing, which does not actively excite the structure, but there are no measurement nodes available that both meet the active-sensing requirements and are useable outside the laboratory. This thesis develops hardware that is low-power, active-sensing and field-deployable. This node uses the impedance method for SHM measurements, and can run the sensor diagnostic algorithm also developed here.Finally, the need for an integrated system for SHM is of primary consideration in this thesis. Without such a system the widespread adoption of SHM will not take place, and this thesis addresses the issue by developing an integrated SHM solution. The solution incorporates active-sensing impedance-measurement based hardware and software with a combination of existing damage-detection algorithms. The result is an integrated system for in-field measurement, validation and analysis of structures. The system specifically incorporates the sensor validation procedure and sensor node also developed in this thesis.In conclusion, recommendations for the future direction of this research topic are made.v AcknowledgementsThere are several people that I could not have completed my thesis without. Dr. GyuhaePark is one, with kind words and positive encouragement he pushed me to finish this paper.

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The application of interferometric techniques to the nondestructive inspection of fiber-reinforced materials

Cited by 42 publications

References 7 publications

Pipeline Structural Health Monitoring Using Macro-fiber Composite Active Sensors

Pipeline Structural Health Monitoring Using Macro-fiber Composite Active Sensors

Feasibility of using impedance‐based damage assessment for pipeline structures

Development and Integration of Hardware and Software for Active-Sensors in Structural Monitoring

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