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Papers by Piervincenzo Rizzo
Review of Scientific Instruments, 2011
In this paper we present the design of two actuators for the generation of highly nonlinear solit... more In this paper we present the design of two actuators for the generation of highly nonlinear solitary waves (HNSWs), which are mechanical waves that can form and travel in highly nonlinear systems. These waves are characterized by a constant spatial wavelength and by a tunable propagation speed, dependent on the wave amplitude. To date, the simplest and widely adopted method
Smart Materials Bulletin, 2000
The main features of the advanced composite bridge that the University of California, San Diego i... more The main features of the advanced composite bridge that the University of California, San Diego is planning to build over interstate I-5 in California are presented. This bridge will utilise a number of fibre-reinforced-polymer components as structural members. The aim of the project is to demonstrate the use of these advanced materials in civil infrastructures. The main focus of this article is the health monitoring plan for the bridge. A number of advanced NDE and conventional methodologies will be used to monitor the bridge behaviour during ...
Journal of The Acoustical Society of America, 2004
This paper deals with the propagation of ultrasonic guided waves in adhesively bonded lap-shear j... more This paper deals with the propagation of ultrasonic guided waves in adhesively bonded lap-shear joints. The topic is relevant to bond inspection by ultrasonic testing. Specifically, the propagation of the lowest-order, antisymmetric a0 mode through the joint is examined. An important aspect is the mode conversion at the boundaries between the single-plate adherents and the multilayer overlap. The a0 strength
Journal of Pressure Vessel Technology-transactions of The Asme, 2005
This paper casts pipe inspection by ultrasonic guided waves in a feature extraction and automatic... more This paper casts pipe inspection by ultrasonic guided waves in a feature extraction and automatic classification framework. The specific defect under investigation is a small notch cut in an ASTM-A53-F steel pipe at depths ranging from 1% to 17% of the pipe cross-...
Journal of Composites for Construction, 2006
The use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates is increasingly bei... more The use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates is increasingly being considered for the rehabilitation of metallic structures. The effective structural monitoring of steel/CFRP adhesive joints is of critical importance to assess the design service performance of the system, which ultimately depends on the bond damage tolerance at the load transfer regions. In the present study laboratory static and fatigue tests were conducted on steel/CFRP skin doubler and double strap joint specimens, which ...
Recent train accidents have reaffirmed the need for developing a rail defect detection system mor... more Recent train accidents have reaffirmed the need for developing a rail defect detection system more effective than that currently used. One of the most promising techniques in rail inspection is the use of ultrasonic guided waves and noncontact probes. A rail inspection prototype based on these concepts and devoted to the automatic damage detection of defects in rail head is the focus of this paper. The prototype includes an algorithm based on wavelet transform and outlier analysis. The discrete wavelet transform is utilized to denoise ultrasonic signals and to generate a set of relevant damage sensitive data. These data are combined into a damage index vector fed to an unsupervised learning algorithm based on outlier analysis that determines the anomalous conditions of the rail. The first part of the paper shows the prototype in action on a railroad track mock-up built at the University of California, San Diego. The mock-up contained surface and internal defects. The results from three experiments are presented. The importance of feature selection to maximize the sensitivity of the inspection system is demonstrated here. The second part of the paper shows the results of field testing conducted in south east Pennsylvania under the auspices of the U.S. Federal Railroad Administration.
ABSTRACT In this paper, we describe the designs and the relative experiments of novel transducers... more ABSTRACT In this paper, we describe the designs and the relative experiments of novel transducers utilized for the generation and detection of highly nonlinear solitary waves (HNSWs). In recent years these waves have been proposed for the NDE/SHM of structural materials and structural elements such as concrete and aluminum lap-joints bonded by high-strength epoxy. Conventionally these transducers contain a chain of spherical particles and the waves are measured by means of thin piezoelectric material embedded in between two half-particles. The final product is usually identified as a bead sensor. Although bead sensors can measure the propagation of HNSWs effectively, their manufacturing may require high level of precision. In this paper we propose an alternative design and investigate the use of magnetostrictive phenomenon to detect HNSWs. For both transducers’ designs a series of experiments are conducted and the results are compared. As the results in good agreement, this study may pave the road to broader applications of HNSWs for NDE and SHM.
ABSTRACT Proof-of-principle numerical simulations demonstrate the technology of ultrasonic tomogr... more ABSTRACT Proof-of-principle numerical simulations demonstrate the technology of ultrasonic tomography for three-dimensional (3-D) imaging of internal rail flaws. New technologies are needed to quantify internal rail flaws so as to ensure increased safety of rail transportation and reduced rail maintenance costs. The technique of ultrasonic tomography was applied to the detection of a 5% head area transverse defect in the rail head. Finite element models of ultrasonic tomographic arrays on a flawed rail were built, followed by an algorithm designed to perform the tomographic imaging of the internal rail flaw in three dimensions. The results showed excellent 3-D imaging performance. The work confirms the potential of ultrasonic tomography for the quantitative verification of internal rail flaws.
ABSTRACT We present a non-destructive inspection method for the structural health monitoring of u... more ABSTRACT We present a non-destructive inspection method for the structural health monitoring of underwater structures. A laser operating at 532 nm is used to excite leaky guided waves on an aluminum plate immersed in water. The plate has a few artificial defects namely vertical notch, horizontal notch, corrosion, and small hole. An array of five immersion transducers arranged in half-circle is used to detect the propagating waves. A signal processing technique is implemented to assess the presence of damage; the method is based on continuous wavelet transform to extract a few damagesensitive features fed to an artificial neural network for damage classification. The experimental results show that the proposed system can be employed for the inspection of underwater plates.
ABSTRACT There is a need in the railroad industry to have quantitative information on internal ra... more ABSTRACT There is a need in the railroad industry to have quantitative information on internal rail flaws, including flaw size and orientation. Such information can lead to knowledge-based decision making on any remedial action, and ultimately increase the safety of train operations by preventing derailments. Current ultrasonic inspection methods leave such sizing determinations to the inspector, and there can be significant variability from one inspector to another depending on experience and other factors. However, this quantitative information can be obtained accurately by 3-D imaging of the rail flaws. It is the goal of this project to develop a portable system that will improve defect classification in rails and ultimately improve public safety.This paper will present a method for 3-D imaging of internal rail flaws based on Ultrasonic Tomography. The proposed technique combines elements of ultrasonic testing with those of radar and sonar imaging to obtain high-resolution images of the flaws using a stationary array of ultrasonic transducers. The array is operated in a “full matrix capture” scheme that minimizes the number of ultrasonic transmitters, hence simplifying the practical implementation and reducing the inspection time. In this method, a full 3D image of the rail volume identifies the location, size and orientation of the defect. This will help to eliminate human error involved with a typical manual inspection using a single transducer probe inspection. The results of advanced numerical simulations, carried out on a rail profile, will be presented. The simulations show the effectiveness of the technique to image a 5% Head Area Transverse Defect in the railhead. Current efforts are aimed at developing an experimental prototype based on this technology, whose design status is also discussed in this paper.
ABSTRACT This paper presents the results of an experimental work where guided ultrasonic waves (G... more ABSTRACT This paper presents the results of an experimental work where guided ultrasonic waves (GUWs) were used for the health monitoring of a real size truss, which was part of a highway variable message sign structure dismantled from service. The monitoring strategy proposed here combines the advantages of GUWs with the extraction of defect-sensitive features to perform a multivariate diagnosis of damage. The effectiveness of the proposed approach is tested by monitoring the propagation of waves along one of the main chords of the truss and by observing the onset and growth of two artificial cracks. The ability to diagnose the presence of these artificial defects located around the welded joints between one main chord and two diagonal members concurring on the weld is discussed. It is shown that by exploiting the stepwise response of the Mahalanobis squared distance, it is possible to discriminate and quantify defects of various sizes; moreover, it is found that certain wave paths better identify the position of damage.
We present a proof-of-principle study about the use of a sensor for the nondestructive monitoring... more We present a proof-of-principle study about the use of a sensor for the nondestructive monitoring of strength development in hydrating concrete. The nondestructive evaluation technique is based on the propagation of highly nonlinear solitary waves (HNSWs), which are non-dispersive mechanical waves that can form and travel in highly nonlinear systems, such as one-dimensional particle chains. A built-in transducer is adopted to excite and detect the HNSWs. The waves are partially reflected at the transducer/concrete interface and partially transmitted into the concrete. The time-of-flight and the amplitude of the waves reflected at the interface are measured and analyzed with respect to the hydration time, and correlated to the initial and final set times established by the penetration test (ASTM C 403). The results show that certain features of the HNSWs change as the concrete curing progresses indicating that it has the potential of being an efficient, cost-effective tool for monitoring strengths/stiffness development.
Review of Scientific Instruments, 2011
In this paper we present the design of two actuators for the generation of highly nonlinear solit... more In this paper we present the design of two actuators for the generation of highly nonlinear solitary waves (HNSWs), which are mechanical waves that can form and travel in highly nonlinear systems. These waves are characterized by a constant spatial wavelength and by a tunable propagation speed, dependent on the wave amplitude. To date, the simplest and widely adopted method
Smart Materials Bulletin, 2000
The main features of the advanced composite bridge that the University of California, San Diego i... more The main features of the advanced composite bridge that the University of California, San Diego is planning to build over interstate I-5 in California are presented. This bridge will utilise a number of fibre-reinforced-polymer components as structural members. The aim of the project is to demonstrate the use of these advanced materials in civil infrastructures. The main focus of this article is the health monitoring plan for the bridge. A number of advanced NDE and conventional methodologies will be used to monitor the bridge behaviour during ...
Journal of The Acoustical Society of America, 2004
This paper deals with the propagation of ultrasonic guided waves in adhesively bonded lap-shear j... more This paper deals with the propagation of ultrasonic guided waves in adhesively bonded lap-shear joints. The topic is relevant to bond inspection by ultrasonic testing. Specifically, the propagation of the lowest-order, antisymmetric a0 mode through the joint is examined. An important aspect is the mode conversion at the boundaries between the single-plate adherents and the multilayer overlap. The a0 strength
Journal of Pressure Vessel Technology-transactions of The Asme, 2005
This paper casts pipe inspection by ultrasonic guided waves in a feature extraction and automatic... more This paper casts pipe inspection by ultrasonic guided waves in a feature extraction and automatic classification framework. The specific defect under investigation is a small notch cut in an ASTM-A53-F steel pipe at depths ranging from 1% to 17% of the pipe cross-...
Journal of Composites for Construction, 2006
The use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates is increasingly bei... more The use of adhesively bonded carbon fiber reinforced polymer (CFRP) laminates is increasingly being considered for the rehabilitation of metallic structures. The effective structural monitoring of steel/CFRP adhesive joints is of critical importance to assess the design service performance of the system, which ultimately depends on the bond damage tolerance at the load transfer regions. In the present study laboratory static and fatigue tests were conducted on steel/CFRP skin doubler and double strap joint specimens, which ...
Recent train accidents have reaffirmed the need for developing a rail defect detection system mor... more Recent train accidents have reaffirmed the need for developing a rail defect detection system more effective than that currently used. One of the most promising techniques in rail inspection is the use of ultrasonic guided waves and noncontact probes. A rail inspection prototype based on these concepts and devoted to the automatic damage detection of defects in rail head is the focus of this paper. The prototype includes an algorithm based on wavelet transform and outlier analysis. The discrete wavelet transform is utilized to denoise ultrasonic signals and to generate a set of relevant damage sensitive data. These data are combined into a damage index vector fed to an unsupervised learning algorithm based on outlier analysis that determines the anomalous conditions of the rail. The first part of the paper shows the prototype in action on a railroad track mock-up built at the University of California, San Diego. The mock-up contained surface and internal defects. The results from three experiments are presented. The importance of feature selection to maximize the sensitivity of the inspection system is demonstrated here. The second part of the paper shows the results of field testing conducted in south east Pennsylvania under the auspices of the U.S. Federal Railroad Administration.
ABSTRACT In this paper, we describe the designs and the relative experiments of novel transducers... more ABSTRACT In this paper, we describe the designs and the relative experiments of novel transducers utilized for the generation and detection of highly nonlinear solitary waves (HNSWs). In recent years these waves have been proposed for the NDE/SHM of structural materials and structural elements such as concrete and aluminum lap-joints bonded by high-strength epoxy. Conventionally these transducers contain a chain of spherical particles and the waves are measured by means of thin piezoelectric material embedded in between two half-particles. The final product is usually identified as a bead sensor. Although bead sensors can measure the propagation of HNSWs effectively, their manufacturing may require high level of precision. In this paper we propose an alternative design and investigate the use of magnetostrictive phenomenon to detect HNSWs. For both transducers’ designs a series of experiments are conducted and the results are compared. As the results in good agreement, this study may pave the road to broader applications of HNSWs for NDE and SHM.
ABSTRACT Proof-of-principle numerical simulations demonstrate the technology of ultrasonic tomogr... more ABSTRACT Proof-of-principle numerical simulations demonstrate the technology of ultrasonic tomography for three-dimensional (3-D) imaging of internal rail flaws. New technologies are needed to quantify internal rail flaws so as to ensure increased safety of rail transportation and reduced rail maintenance costs. The technique of ultrasonic tomography was applied to the detection of a 5% head area transverse defect in the rail head. Finite element models of ultrasonic tomographic arrays on a flawed rail were built, followed by an algorithm designed to perform the tomographic imaging of the internal rail flaw in three dimensions. The results showed excellent 3-D imaging performance. The work confirms the potential of ultrasonic tomography for the quantitative verification of internal rail flaws.
ABSTRACT We present a non-destructive inspection method for the structural health monitoring of u... more ABSTRACT We present a non-destructive inspection method for the structural health monitoring of underwater structures. A laser operating at 532 nm is used to excite leaky guided waves on an aluminum plate immersed in water. The plate has a few artificial defects namely vertical notch, horizontal notch, corrosion, and small hole. An array of five immersion transducers arranged in half-circle is used to detect the propagating waves. A signal processing technique is implemented to assess the presence of damage; the method is based on continuous wavelet transform to extract a few damagesensitive features fed to an artificial neural network for damage classification. The experimental results show that the proposed system can be employed for the inspection of underwater plates.
ABSTRACT There is a need in the railroad industry to have quantitative information on internal ra... more ABSTRACT There is a need in the railroad industry to have quantitative information on internal rail flaws, including flaw size and orientation. Such information can lead to knowledge-based decision making on any remedial action, and ultimately increase the safety of train operations by preventing derailments. Current ultrasonic inspection methods leave such sizing determinations to the inspector, and there can be significant variability from one inspector to another depending on experience and other factors. However, this quantitative information can be obtained accurately by 3-D imaging of the rail flaws. It is the goal of this project to develop a portable system that will improve defect classification in rails and ultimately improve public safety.This paper will present a method for 3-D imaging of internal rail flaws based on Ultrasonic Tomography. The proposed technique combines elements of ultrasonic testing with those of radar and sonar imaging to obtain high-resolution images of the flaws using a stationary array of ultrasonic transducers. The array is operated in a “full matrix capture” scheme that minimizes the number of ultrasonic transmitters, hence simplifying the practical implementation and reducing the inspection time. In this method, a full 3D image of the rail volume identifies the location, size and orientation of the defect. This will help to eliminate human error involved with a typical manual inspection using a single transducer probe inspection. The results of advanced numerical simulations, carried out on a rail profile, will be presented. The simulations show the effectiveness of the technique to image a 5% Head Area Transverse Defect in the railhead. Current efforts are aimed at developing an experimental prototype based on this technology, whose design status is also discussed in this paper.
ABSTRACT This paper presents the results of an experimental work where guided ultrasonic waves (G... more ABSTRACT This paper presents the results of an experimental work where guided ultrasonic waves (GUWs) were used for the health monitoring of a real size truss, which was part of a highway variable message sign structure dismantled from service. The monitoring strategy proposed here combines the advantages of GUWs with the extraction of defect-sensitive features to perform a multivariate diagnosis of damage. The effectiveness of the proposed approach is tested by monitoring the propagation of waves along one of the main chords of the truss and by observing the onset and growth of two artificial cracks. The ability to diagnose the presence of these artificial defects located around the welded joints between one main chord and two diagonal members concurring on the weld is discussed. It is shown that by exploiting the stepwise response of the Mahalanobis squared distance, it is possible to discriminate and quantify defects of various sizes; moreover, it is found that certain wave paths better identify the position of damage.
We present a proof-of-principle study about the use of a sensor for the nondestructive monitoring... more We present a proof-of-principle study about the use of a sensor for the nondestructive monitoring of strength development in hydrating concrete. The nondestructive evaluation technique is based on the propagation of highly nonlinear solitary waves (HNSWs), which are non-dispersive mechanical waves that can form and travel in highly nonlinear systems, such as one-dimensional particle chains. A built-in transducer is adopted to excite and detect the HNSWs. The waves are partially reflected at the transducer/concrete interface and partially transmitted into the concrete. The time-of-flight and the amplitude of the waves reflected at the interface are measured and analyzed with respect to the hydration time, and correlated to the initial and final set times established by the penetration test (ASTM C 403). The results show that certain features of the HNSWs change as the concrete curing progresses indicating that it has the potential of being an efficient, cost-effective tool for monitoring strengths/stiffness development.