We experimentally investigate a diagnostic technique for identifying a weak bond in composites us... more We experimentally investigate a diagnostic technique for identifying a weak bond in composites using highly nonlinear solitary waves (HNSWs). We set up a one-dimensional chain of granular crystals, consisting of spherical particles with nonlinear interactions, to generate HNSWs. These solitary wave packets are transmitted into an inspection area of composites by making a direct contact with the chain. We demonstrate that a strong type of solitary waves injected to the weak bond area can break the weak bond of laminates, thereby causing delamination. Then, to identify the creation of the delamination, we transmit a weak type of solitary waves by employing the same apparatus, and measure the solitary waves reflected from the specimens. By analyzing these reflected solitary waves, we differentiate the weak bond samples with the pristine bond ones in an efficient and fast manner. The diagnostic results based on the proposed method are compared with the strength and energy release rate at bond interfaces, which are measured via standard testing methods such as three point bending and end notched flexure tests. This study shows the potential of solitary wave-based detection of weak bonds for hot spot monitoring of composite-based structures.
Structural Health Monitoring-an International Journal, 2019
Asset monitoring is a critical factor for a wide variety of commercial assets where accidents due... more Asset monitoring is a critical factor for a wide variety of commercial assets where accidents due to structural usage, structural fatigue and impact damage are relatively common. Flexible multi-functional sensor layers can conformably distribute sensors over very large areas and enable availability of instantaneous information on the structural integrity of the asset, measure environmental conditions for optimum performance while adding minimal weight. Key factors in enabling reliable monitoring using the sensor layers are 1) Accurate and fast installation on platforms of any size and shape 2) Survival of the sensors in extreme environments that the asset is subjected to 3) Self-diagnostic capabilities to ensure accurate functioning of the sensors and 4) Low-cost of repair/replacement This paper will provide insights into new developments in the reliable usage of multifunctional sensor layers on assets in extreme environments in the field. Details on new methods developed to minimiz...
To ensure the safety of high speed trains during the entire lifetime of operation, an effective o... more To ensure the safety of high speed trains during the entire lifetime of operation, an effective operational concept utilizing on-train/online SHM systems with existing scheduled maintenance procedures is crucially in demand. Online monitoring technologies have reshaped the traditional periodic maintenance procedures to condition-based maintenance procedures which have the benefits of enhancing the safety of trains and decreasing the cost of maintenance. The SHM solution for the high speed Electric Multiple Units (EMU) application performing real-time monitoring of the train bolster structure is called Active Train Online Monitoring System (ATOMS). The system comprises of the SMART Layers™ sensor network, Onboard ScanGenie data acquisition hardware, and a central computer with SHM Patch data analysis software installed. The SMART Layers™ are surface mounted at critical structural locations on the train using aerospace grade installation materials along with robust connectors to conne...
Weak bond detection in composites using solitary waves Taru Singhal Chair of the Supervisory Comm... more Weak bond detection in composites using solitary waves Taru Singhal Chair of the Supervisory Committee: Assistant Professor Professor Jinkyu Yang Aeronautics and Astronautics A composite material is composed of fibers embedded in a matrix and is called Fiber Reinforced Plastic (FRP). Particularly, Carbon Fiber Reinforced Plastic (CFRP) has carbon fiber as the reinforcement. It has a high strength-to-weight ratio and is not less susceptible to fatigue or corrosion compared to metallic materials. Therefore, composite materials like CFRP find applications in aerospace industry due to their low weight and advanced mechanical properties. For large scale composite structures, smaller parts often need to be connected together. The connection of these parts could be done either by mechanical joints such as fasteners or by gluing them together using adhesives. This research focuses on bonded composite structures. A prevailing problem in bonded joints is the indeterminate nature of the streng...
Structural Health Monitoring-an International Journal, 2017
Monitoring the continued health of aircraft subsystems and identifying problems before they affec... more Monitoring the continued health of aircraft subsystems and identifying problems before they affect airworthiness has been a long-term goal of the aviation industry. Towards this end, Structural Health Monitoring (SHM) systems that could be used for the in-service monitoring of the health of new and existing aircraft structures are being matured. This paper will go step-by-step into the various challenges associated with meeting preliminary certification compliance requirements. A 5-year program completed under funding from the Federal Aviation Administration will be used as a guide to lead the reader through the various certification compliance steps The objectives of this program were to (1) develop, validate, and demonstrate Smart Patch System (SPS) technologies including advanced software, algorithms, and methodologies for structures and dynamic components to (a) detect fatigue cracks and damages before exceeding critical threshold or incipient failure and (b) characterize fatigu...
An effective onboard structural health monitoring (SHM) system- ATOMS, is proposed to reshape tra... more An effective onboard structural health monitoring (SHM) system- ATOMS, is proposed to reshape traditional scheduled maintenance practices for condition-based maintenance procedures to enhance train safety and to reduce the cost of maintenance. A complete train lifecycle safety management program is envisioned to involve data collection, data processing, information dissemination, data and information storage, and operational decision management and control. To address the requirements, ATOMS - Active Train Online Monitoring System is developed as a complete SHM solution for the high speed Electric Multiple Units (EMU) applications. ATOMS provides: (1) real-time health-centric operation; (2) on-demand structural health diagnostics; (3) diagnostics-assisted prognostics; and (4) proactive maintenance.
As the volumes of service of subways and high-speed Electric Multiple Units (EMU) trains have sig... more As the volumes of service of subways and high-speed Electric Multiple Units (EMU) trains have significantly grown in recent years, the life cycle maintenance operation plan for these newly delivered rail vehicles becomes critical. Emerging structural health monitoring (SHM) technologies are introduced to revolutionize the operational procedures for the maintenance of these rail vehicles. To ensure the train safety during the whole lifetime of operation, an effective operation concept to integrate the on-train/online SHM systems with the existing scheduled maintenance procedures is crucially in demand. High-speed EMU trains are obligated with their maintenance schedules before they are delivered to passenger transportation services. The vision of a complete train lifecycle management model will involve multiple tiers in data collection, data distribution and information dissemination, data networking, big data storage and processing, and operational decision management and control
The new generation of Industrial Internet of Things (IIOT) will transform the Industrial Age to t... more The new generation of Industrial Internet of Things (IIOT) will transform the Industrial Age to the Information Age by exploiting opportunities and benefits offered by Information Age technology and techniques. Assets and infrastructure continue to drive innovation in systems and deployment of IOT technologies that have the potential to deliver new capabilities and cost savings. A key enabler for IIOT are sensors and data procured from them. Sensor based IOT devices can gather more data, facilitate more complex analysis and faster reactions, and reduce human error, delivering more precise and efficient military capabilities. Sensor network based Structural Health Monitoring (SHM) systems have the potential to provide real-time and historical sensor based data on the integrity of any structural platform to enable IIOT. SHM systems can reliably detect, localize and quantify damage in components in existing and new structural assets and use the identified damage to make a decision on w...
We experimentally investigate a diagnostic technique for identifying a weak bond in composites us... more We experimentally investigate a diagnostic technique for identifying a weak bond in composites using highly nonlinear solitary waves. We set up a one-dimensional chain of granular crystals, consisting of spherical particles with nonlinear interactions, to generate highly nonlinear solitary waves. These solitary wave packets are transmitted into an inspection area of composites by making a direct contact with the chain. We demonstrate that a strong type of solitary waves injected to the weak bond area can break the weak bond of laminates, thereby causing delamination. Then, to identify the creation of the delamination, we transmit a weak type of solitary waves by employing the same apparatus, and measure the solitary waves reflected from the specimens. By analyzing these reflected solitary waves, we differentiate the weak bond samples with the pristine bond ones in an efficient and fast manner. The diagnostic results based on the proposed method are compared with the strength and energy release rate at bond interfaces, which are measured via standard testing methods such as three point bending and end notched flexure tests. This study shows the potential of solitary wave-based detection of weak bonds for hot spot monitoring of composite-based structures. ‡ Equally contributed first author
We experimentally investigate a diagnostic technique for identifying a weak bond in composites us... more We experimentally investigate a diagnostic technique for identifying a weak bond in composites using highly nonlinear solitary waves (HNSWs). We set up a one-dimensional chain of granular crystals, consisting of spherical particles with nonlinear interactions, to generate HNSWs. These solitary wave packets are transmitted into an inspection area of composites by making a direct contact with the chain. We demonstrate that a strong type of solitary waves injected to the weak bond area can break the weak bond of laminates, thereby causing delamination. Then, to identify the creation of the delamination, we transmit a weak type of solitary waves by employing the same apparatus, and measure the solitary waves reflected from the specimens. By analyzing these reflected solitary waves, we differentiate the weak bond samples with the pristine bond ones in an efficient and fast manner. The diagnostic results based on the proposed method are compared with the strength and energy release rate at bond interfaces, which are measured via standard testing methods such as three point bending and end notched flexure tests. This study shows the potential of solitary wave-based detection of weak bonds for hot spot monitoring of composite-based structures.
Structural Health Monitoring-an International Journal, 2019
Asset monitoring is a critical factor for a wide variety of commercial assets where accidents due... more Asset monitoring is a critical factor for a wide variety of commercial assets where accidents due to structural usage, structural fatigue and impact damage are relatively common. Flexible multi-functional sensor layers can conformably distribute sensors over very large areas and enable availability of instantaneous information on the structural integrity of the asset, measure environmental conditions for optimum performance while adding minimal weight. Key factors in enabling reliable monitoring using the sensor layers are 1) Accurate and fast installation on platforms of any size and shape 2) Survival of the sensors in extreme environments that the asset is subjected to 3) Self-diagnostic capabilities to ensure accurate functioning of the sensors and 4) Low-cost of repair/replacement This paper will provide insights into new developments in the reliable usage of multifunctional sensor layers on assets in extreme environments in the field. Details on new methods developed to minimiz...
To ensure the safety of high speed trains during the entire lifetime of operation, an effective o... more To ensure the safety of high speed trains during the entire lifetime of operation, an effective operational concept utilizing on-train/online SHM systems with existing scheduled maintenance procedures is crucially in demand. Online monitoring technologies have reshaped the traditional periodic maintenance procedures to condition-based maintenance procedures which have the benefits of enhancing the safety of trains and decreasing the cost of maintenance. The SHM solution for the high speed Electric Multiple Units (EMU) application performing real-time monitoring of the train bolster structure is called Active Train Online Monitoring System (ATOMS). The system comprises of the SMART Layers™ sensor network, Onboard ScanGenie data acquisition hardware, and a central computer with SHM Patch data analysis software installed. The SMART Layers™ are surface mounted at critical structural locations on the train using aerospace grade installation materials along with robust connectors to conne...
Weak bond detection in composites using solitary waves Taru Singhal Chair of the Supervisory Comm... more Weak bond detection in composites using solitary waves Taru Singhal Chair of the Supervisory Committee: Assistant Professor Professor Jinkyu Yang Aeronautics and Astronautics A composite material is composed of fibers embedded in a matrix and is called Fiber Reinforced Plastic (FRP). Particularly, Carbon Fiber Reinforced Plastic (CFRP) has carbon fiber as the reinforcement. It has a high strength-to-weight ratio and is not less susceptible to fatigue or corrosion compared to metallic materials. Therefore, composite materials like CFRP find applications in aerospace industry due to their low weight and advanced mechanical properties. For large scale composite structures, smaller parts often need to be connected together. The connection of these parts could be done either by mechanical joints such as fasteners or by gluing them together using adhesives. This research focuses on bonded composite structures. A prevailing problem in bonded joints is the indeterminate nature of the streng...
Structural Health Monitoring-an International Journal, 2017
Monitoring the continued health of aircraft subsystems and identifying problems before they affec... more Monitoring the continued health of aircraft subsystems and identifying problems before they affect airworthiness has been a long-term goal of the aviation industry. Towards this end, Structural Health Monitoring (SHM) systems that could be used for the in-service monitoring of the health of new and existing aircraft structures are being matured. This paper will go step-by-step into the various challenges associated with meeting preliminary certification compliance requirements. A 5-year program completed under funding from the Federal Aviation Administration will be used as a guide to lead the reader through the various certification compliance steps The objectives of this program were to (1) develop, validate, and demonstrate Smart Patch System (SPS) technologies including advanced software, algorithms, and methodologies for structures and dynamic components to (a) detect fatigue cracks and damages before exceeding critical threshold or incipient failure and (b) characterize fatigu...
An effective onboard structural health monitoring (SHM) system- ATOMS, is proposed to reshape tra... more An effective onboard structural health monitoring (SHM) system- ATOMS, is proposed to reshape traditional scheduled maintenance practices for condition-based maintenance procedures to enhance train safety and to reduce the cost of maintenance. A complete train lifecycle safety management program is envisioned to involve data collection, data processing, information dissemination, data and information storage, and operational decision management and control. To address the requirements, ATOMS - Active Train Online Monitoring System is developed as a complete SHM solution for the high speed Electric Multiple Units (EMU) applications. ATOMS provides: (1) real-time health-centric operation; (2) on-demand structural health diagnostics; (3) diagnostics-assisted prognostics; and (4) proactive maintenance.
As the volumes of service of subways and high-speed Electric Multiple Units (EMU) trains have sig... more As the volumes of service of subways and high-speed Electric Multiple Units (EMU) trains have significantly grown in recent years, the life cycle maintenance operation plan for these newly delivered rail vehicles becomes critical. Emerging structural health monitoring (SHM) technologies are introduced to revolutionize the operational procedures for the maintenance of these rail vehicles. To ensure the train safety during the whole lifetime of operation, an effective operation concept to integrate the on-train/online SHM systems with the existing scheduled maintenance procedures is crucially in demand. High-speed EMU trains are obligated with their maintenance schedules before they are delivered to passenger transportation services. The vision of a complete train lifecycle management model will involve multiple tiers in data collection, data distribution and information dissemination, data networking, big data storage and processing, and operational decision management and control
The new generation of Industrial Internet of Things (IIOT) will transform the Industrial Age to t... more The new generation of Industrial Internet of Things (IIOT) will transform the Industrial Age to the Information Age by exploiting opportunities and benefits offered by Information Age technology and techniques. Assets and infrastructure continue to drive innovation in systems and deployment of IOT technologies that have the potential to deliver new capabilities and cost savings. A key enabler for IIOT are sensors and data procured from them. Sensor based IOT devices can gather more data, facilitate more complex analysis and faster reactions, and reduce human error, delivering more precise and efficient military capabilities. Sensor network based Structural Health Monitoring (SHM) systems have the potential to provide real-time and historical sensor based data on the integrity of any structural platform to enable IIOT. SHM systems can reliably detect, localize and quantify damage in components in existing and new structural assets and use the identified damage to make a decision on w...
We experimentally investigate a diagnostic technique for identifying a weak bond in composites us... more We experimentally investigate a diagnostic technique for identifying a weak bond in composites using highly nonlinear solitary waves. We set up a one-dimensional chain of granular crystals, consisting of spherical particles with nonlinear interactions, to generate highly nonlinear solitary waves. These solitary wave packets are transmitted into an inspection area of composites by making a direct contact with the chain. We demonstrate that a strong type of solitary waves injected to the weak bond area can break the weak bond of laminates, thereby causing delamination. Then, to identify the creation of the delamination, we transmit a weak type of solitary waves by employing the same apparatus, and measure the solitary waves reflected from the specimens. By analyzing these reflected solitary waves, we differentiate the weak bond samples with the pristine bond ones in an efficient and fast manner. The diagnostic results based on the proposed method are compared with the strength and energy release rate at bond interfaces, which are measured via standard testing methods such as three point bending and end notched flexure tests. This study shows the potential of solitary wave-based detection of weak bonds for hot spot monitoring of composite-based structures. ‡ Equally contributed first author
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