Showing papers in "Structural Health Monitoring-an International Journal in 2017"
TL;DR: In this paper, a multifunctional cement composite that could not only bear loads but also possessed electromechanical properties that are sensitive to damage was designed, and the objective of the study was to design a composite composite that was robust to damage.
Abstract: The objective of this study was to design a multifunctional cement composite that could not only bear loads but also possessed electromechanical properties that are sensitive to damage. A mainstrea...
113 citations
TL;DR: A new approach for detecting structural damage using transmissibility together with hierarchical clustering and similarity analysis is proposed in this article, which is derived from the structural dynamic responses characterizing the structural state.
Abstract: Maintenance and repairing in actual engineering for long-term used structures, such as pipelines and bridges, make structural damage detection indispensable, as an unanticipated damage may give rise to a disaster, leading to huge economic loss. A new approach for detecting structural damage using transmissibility together with hierarchical clustering and similarity analysis is proposed in this study. Transmissibility is derived from the structural dynamic responses characterizing the structural state. First, for damage detection analysis, hierarchical clustering analysis is adopted to discriminate the damaged scenarios from an unsupervised perspective, taking transmissibility as feature for discriminating damaged patterns from undamaged ones. This is unlike directly predicting the structural damage from the indicators manifestation, as sometimes this can be vague due to the small difference between damaged scenarios and the intact baseline. For comparison reasons, cosine similarity measure and distance me...
78 citations
TL;DR: In this paper, the potential of a baseline-free structural health monito-conditioning system was investigated, and the authors investigated the potential for the detection and characterization of delamination damage.
Abstract: Detection and characterization of delamination damage are of great importance to the assurance of structural safety. This work investigates the potential of a baseline-free structural health monito...
71 citations
TL;DR: In this article, a structural health monitoring system that is able to detect structural defects of wind turbine blade such as cracks, leading/trailing-edge opening, or delamination is presented.
Abstract: This study presents a structural health monitoring system that is able to detect structural defects of wind turbine blade such as cracks, leading/trailing-edge opening, or delamination. It is shown...
64 citations
TL;DR: In this article, the effects of axial compressive loading on the monitoring results are investigated, and the results indicate that the baselines of monitoring signals obtained from the same concrete structure in its healthy state can vary under different stress levels.
Abstract: Piezoceramic-based smart aggregate has been widely used to evaluate early-age concrete strength and to detect damage in concrete structures. In these structural health monitoring systems, they are generally verified and calibrated through experiments under load-free condition. However, the stress levels of actual concrete members are different. The microstructures of concrete will change with the variation of external load, and the high-frequency waves used in the monitoring system may be highly sensitive to these changes. In this study, the effects of axial compressive loading on the monitoring results are investigated. Specifically, three loading cases, that is, single cycle load, cyclic load, and step-by-step load, are employed to stress the concrete specimens embedded with smart aggregates. The amplitude and velocity of monitoring signals were measured before, during, and after each loading case. The test results show that the axial load lower than 30% of failure load still have a significant impact on the received signals. The amplitude attenuation is dependent on both frequency and load history, while the velocity is highly stress-dependent. The results indicate that the baselines of monitoring signals obtained from the same concrete structure in its healthy state can vary under different stress levels. The axial load variation should be carefully considered during the monitoring process. This study also provides a potential method to assess stress state in concrete structures using smart aggregates.
56 citations
TL;DR: In this article, structural health monitoring offers an attractive tool for condition assessment, fault prognosis and life-cycle management of wind turbine components, but owing to the intense loading conditio...
Abstract: Structural health monitoring offers an attractive tool for condition assessment, fault prognosis and life-cycle management of wind turbine components. However, owing to the intense loading conditio...
54 citations
TL;DR: In this article, the Akaike Information Criteria (AIC) was used to improve the performance of delta-t mapping for acoustic emission detection in complex structures and materials, in which the difficulties in identifying the precise arrival time of an AE signal are addressed by incorporating the AIC.
Abstract: In order to overcome the difficulties in applying traditional Time-Of Arrival (TOA) techniques for locating Acoustic Emission (AE) events in complex structures and materials, a technique termed “delta-t mapping” was developed. This paper presents a significant improvement on this, in which the difficulties in identifying the precise arrival time of an AE signal are addressed by incorporating the Akaike Information Criteria (AIC). The performance of the TOA, the delta-t mapping and the AIC delta-t mapping techniques is assessed by locating artificial AE sources, fatigue damage and impact events in aluminium and composite materials respectively. For all investigations conducted the improved AIC delta-t technique shows a reduction in average Euclidean source location error irrespective of material or source type. For locating H-N sources on a complex aluminium specimen the average source location error (Euclidean) is 32.6, (TOA), 5.8 (delta-t) and 3mm (AIC delta-t). For locating fatigue damage on the same specimen the average error is 20.2, (TOA), 4.2 (delta-t) and 3.4mm (AIC delta-t). For locating H-N sources on a composite panel the average error is 19.3, (TOA), 18.9 (delta-t) and 4.2mm (AIC delta-t). Finally the AIC delta-t mapping technique had the lowest average error (3.3mm) when locating impact events when compared with the delta-t (18.9mm) and TOA (124.7mm) techniques. Overall the AIC delta-t mapping technique is the only technique which demonstrates consistently the lowest average source location error (greatest average error 4.2mm) when compared with the delta-t (greatest average error 18.9mm) and TOA (greatest average error 124.7mm) techniques. These results demonstrate that the AIC delta-t mapping technique is a viable option for AE source location, increasing the accuracy and likelihood of damage detection, irrespective of material, geometry and source type.
48 citations
TL;DR: The acoustic emission technique is widely used for mechanical diagnostics and damage characterization in reinforced concrete structures this article, and the feasibility of using acoustic emission for structural analysis is investigated in this article.
Abstract: The acoustic emission technique is widely used for mechanical diagnostics and damage characterization in reinforced concrete structures. This article experimentally investigated the feasibility of ...
44 citations
TL;DR: In this article, structural health monitoring (SHM) is integrated with damage progression models to form a probabilistic prediction of a structure's rema... using inverse uncertainty quantification techniques.
Abstract: Utilizing inverse uncertainty quantification techniques, structural health monitoring (SHM) can be integrated with damage progression models to form a probabilistic prediction of a structure’s rema...
43 citations
TL;DR: In this paper, a non-contacting measurement technique based on acoustic monitoring is proposed to detect cracks or damage within a structure by observing sound radiation using a single microphone or a b...
Abstract: This article proposes a non-contacting measurement technique based on acoustic monitoring to detect cracks or damage within a structure by observing sound radiation using a single microphone or a b...
43 citations
TL;DR: In this paper, the impedance-based structural health monitoring technique is used in a damage detection problem considering temperature variation effects, and a method to statistically determine a threshold for damage detection purposes using concepts of statistical process control, as well as confidence int...
Abstract: The impedance-based structural health monitoring method has become a promising and attractive tool for damage identification and is considered a nondestructive evaluation technique. However, conventional impedance-based structural health monitoring studies have mainly focused on structural damage identification but not so much on statistical modeling approaches in order to determine a threshold for the decision making of the damage detection system. In this study, the impedance-based structural health monitoring technique is used in a damage detection problem considering temperature variation effects. For this aim, three aluminum 2024-T3 plates were instrumented with small lead zirconate titanate patches close to their borders, and damage was introduced in the central position of the plates, with temperature ranging from −10°C to 60°C. This article proposes a method to statistically determine a threshold for damage detection purposes using concepts of statistical process control, as well as confidence int...
TL;DR: A combination of plate-guided ultrasound and air-coupled ultrasonics is used to locate and visualize delaminations in composite laminates using wave visualization method as mentioned in this paper.
Abstract: This article reports on the characterization of delamination damages in composite laminates using wave visualization method. A combination of plate-guided ultrasound and air-coupled ultrasonics is used to locate and visualize delaminations. The study focuses on the physics of Lamb wave propagation and interaction with delaminations at various through-thickness locations and positions. Three-dimensional finite element simulations are used to study, in detail, the changes in wave features such as mode velocity, wavelength and wave refraction in the delamination region. These wave features provide information on the location, position and orientation of the delamination. These studies are validated by experimental measurements. The influence of position of source and delamination on wave refraction in the delamination region is examined. This method also correlates the results obtained from experiments and finite element simulations to theoretical dispersion curves in order to distinctly determine the delami...
TL;DR: An effective way to deal with noisy guided-wave signals for damage detection as well as for de-noising is developed using a robust sparse Bayesian learning algorithm.
Abstract: Guided waves have been used for structural health monitoring to detect damage or defects in structures. However, guided wave signals often involve multiple modes and noise. Extracting meaningful da...
TL;DR: An adaptive guided wave-Gaussian mixture model–based damage monitoring method is proposed that can be used online without any structural mechanical model and a priori knowledge of damage under time-varying conditions and is validated in a full-scale aircraft fatigue test.
Abstract: Structural health monitoring technology has gradually developed from the research in laboratory to engineering validations and applications. However, the problem of reliable damage evaluation under...
TL;DR: In this article, the feasibility of application of the very recent multi-parameter probability of detection approach, developed within the framework of guided wave-based structural health monitoring, was investigated.
Abstract: In view of an extensive literature about guided waves–based structural health monitoring of plate-like structures made of metallic and composite materials, a lack of information is pointed out regarding an effective and universally accepted approach for characterizing capability and reliability in detecting, localizing and sizing in-service damages. On the other hand, in the frame of traditional non-destructive testing systems, capability is typically expressed by means of suitable ‘probability of detection’ curves based on Berens’ model, where a linear relationship is established between probability of detection and flaw size. Although the uncertain factors are usually different between a non-destructive inspection technique and a structural health monitoring approach, it seems that a similar mathematical framework could be assumed. From this point of view, this research investigates the feasibility of application of the very recent ‘multi-parameter’ probability of detection approach, developed within th...
TL;DR: A fatigue crack and its precursor often serves as a source of nonlinear mechanism for ultrasonic waves, and nonlinear ultrasonic techniques have been widely studied to detect fatigue crack at its v... as mentioned in this paper.
Abstract: A fatigue crack and its precursor often serves as a source of nonlinear mechanism for ultrasonic waves, and nonlinear ultrasonic techniques have been widely studied to detect fatigue crack at its v...
TL;DR: This paper introduces a mathematical methodology that establishes the data-driven design and decision problem associated with Digital Thread and establishes a methodology for how information along the Digital Thread enters into the design problem as well how design decisions affect the Digitalthread.
Abstract: Digital Thread offers the opportunity to use information generated across the product lifecycle to design the next generation of products. In this paper, we introduce a mathematical methodology that establishes the data-driven design and decision problem associated with Digital Thread. Our objectives are twofold: 1) Provide a mathematical definition of Digital Thread in the context of conceptual and preliminary design and establish a methodology for how information along the Digital Thread enters into the design problem as well how design decisions affect the Digital Thread. 2) Develop a data-driven design method that incorporates data from different sources from across the product life cycle. We illustrate aspects of our methodology through an example design of a structural fiber-steered composite component.
TL;DR: In this article, a two-dimensional noncontact, areal scanning system was presented to image and quantify multiple sites of damage in isotropic plates using reverse-time migration with a normalized zero-la...
Abstract: This article presents a two-dimensional, non-contact, areal scanning system to image and quantify multiple sites of damage in isotropic plates using reverse-time migration with a normalized zero-la...
TL;DR: In this paper, the authors evaluated fatigue-induced disbond areas in carbon fiber-reinforced polymer double-lap joints using embedded fiber Bragg grating sensors, and the relationship between the peak intensity ratio and the length was analyzed by coupled structural-optical analysis.
Abstract: This study evaluated fatigue-induced disbond areas in carbon fiber–reinforced polymer double-lap joints using embedded fiber Bragg grating sensors. When the disbond grew by cyclic loading, the embedded fiber Bragg grating sensors yielded reflection spectra having two peaks representing a step-like strain distribution generated by the disbond; the peak at the shorter wavelength corresponded to the unloaded disbond region. The ratio of the peak intensity at the shorter wavelength to that at the longer wavelength increased gradually with increasing disbond length. The relationship between the peak intensity ratio and the disbond length was analyzed by coupled structural–optical analysis and was validated by comparing analytical peak intensity ratio with the experiment results. The disbond length was then estimated from the measured spectra based on this analytical calibration relationship, but the estimated disbond area exceeded that observed using the ultrasonic C-scan technique. Additional experiments incl...
TL;DR: In this article, an electrical impedance tomography (EIT)-based multifunctional surface sensing system, or sensing skin, was proposed for structural health monitoring, where the EIT-based sensing skin was developed for detecting and localizing the ingress of chlorides and cracking.
Abstract: In this paper, we propose an electrical impedance tomography (EIT)-based multifunctional surface sensing system, or sensing skin, for structural health monitoring. More specifically, the EIT-based sensing skin is developed for detecting and localizing the ingress of chlorides and cracking: two phenomena which are of concern in many structures, including reinforced concrete structures. The multifunctional sensing skin is made of two layers: one layer is sensitive to both chlorides and cracking, and the other layer is sensitive to cracking only. In the experiments, the sensing skin is tested on a polymeric and concrete substrate. The results demonstrate the feasibility of using the multifunctional multi-layer sensing skin for detecting and localizing corrosive elements and cracking, and for distinguishing between them.
TL;DR: In this paper, a discrete Volterra model is used to monitor the prediction error of a reference model representing the healthy structure, which can separate the linear and nonlinear components of the response of a system.
Abstract: Nonlinearities in the dynamical behavior of mechanical systems can degrade the performance of damage detection features based on a linearity assumption. In this article, a discrete Volterra model is used to monitor the prediction error of a reference model representing the healthy structure. This kind of model can separate the linear and nonlinear components of the response of a system. This property of the model is used to compare the consequences of assuming a nonlinear model during the nonlinear regime of a magneto-elastic system. Hypothesis tests are then employed to detect variations in the statistical properties of the damage features. After these analyses, conclusions are made about the application of Volterra series in damage detection.
TL;DR: In this article, the problem of random-vibration-based damage diagnosis, including detection and localization, for a lab-scale aircraft stabilizer structure is addressed, based on the recently introduced introduction of the so-called "random-vibrations" approach.
Abstract: The problem of random-vibration-based damage diagnosis, including detection and localization, for a lab–scale aircraft stabilizer structure is addressed. Diagnosis is based on the recently introduc...
TL;DR: A root mean square–based probability density function is proposed to improve the efficiency of entropy measures and suggest the effective fault diagnosis using proposed method.
Abstract: Fault diagnosis of gearbox which operates on low rotating speed with high fluctuations is highly important because its ignorance can led to a catastrophe. The uncertainty within the vibration signa...
TL;DR: In this article, a new monitoring system is proposed based on the heating technique incorporated in the temperature tracer method, that is, the integrated system of fiber Bragg temperature sensing and hydrothermal cycling.
Abstract: In order to make up defects liable for the conventional monitoring of rockfill dam seepage in spatial inconsequence and low efficiency, a new monitoring system is proposed based on the heating technique incorporated in the temperature tracer method, that is, the integrated system of fiber Bragg grating temperature sensing and hydrothermal cycling. The system has a boiler as its heating device, and heated water from boiler is admitted through redistributor and circular warm pipelines, in which fiber Bragg grating sensors are embedded in advance for measuring the water temperature, thereby the seepage behavior is identified from the correlative fields of temperature and seepage. A coefficient ζv, according to Newton’s law of cooling, is then fitted out by pipeline cooling curves and used as a new way to identify the seepage state. The temperature–time–travel curves for the cooling period have proved by calibration tests to be, in general, consistent with the mathematical model of temperature variations unde...
TL;DR: The numerical simulation and the practical application test obtained satisfactory results when combining the wavelet transform, intrinsic time-scale decomposition and linear clustering sparse component analysis, thereby proving the validity of this method.
Abstract: Rolling bearings, as important machinery components, strongly affect the operation of machines. Early bearing fault diagnosis methods commonly take time–frequency analysis as the fundamental basis,...
TL;DR: In this paper, structural integrity inspections of wind turbine blades are typically carried out by the use of rope or platform access, since these inspection approaches are both tedious and extremely cost-consuming.
Abstract: Today, structural integrity inspections of wind turbine blades are typically carried out by the use of rope or platform access. Since these inspection approaches are both tedious and extremely cost...
TL;DR: A novel system for passively monitoring hand-washing activities through minimal cost-effective sensors with no requirements for additional staff or intrusive wearable sensors that achieves an average classification accuracy of 95.4% with real-world experiments.
Abstract: In this paper, we present a novel system for monitoring hand-washing activities using vibration sensing of the sink structure In the United States alone, more than 17 million patients each year are subjected to preventable infections in the hospital Proper handwashing practices are essential for reducing these hospital-acquired infections Existing approaches for monitoring hand-washing practices include visual observation, wearable sensing, and cameras These approaches have been limited due to logistical challenges, deployment cost, and intrusiveness Our system detects and monitors hand-washing activities by measuring the vibration response of the sink structure due to the hand-washing activities We utilize the key insight that each activity associated with hand-washing (eg water running, soap dispenser actuating, hands rinsing with water, etc) generates unique structural vibration responses in the sink structure Our approach has the advantage of passively monitoring hand-washing activities through minimal cost-effective sensors with no requirements for additional staff or intrusive wearable sensors The main research question is how to identify governing features that can distinguish the structural vibration responses due to each hand-washing activity Our approach investigates the energy distribution of the vibration signal response from each hand-washing activity in the frequency domain This approach uses the insight that each hand-washing activity generates different responses in the natural frequencies of the sink structure Our method achieves an average classification accuracy of 954% with real-world experiments
TL;DR: Structural health monitoring is widely applied in industrial sectors as it reduces costs associated with maintenance intervals and manual inspections of damage in sensitive structures, while enhanc... as discussed by the authors,... ).
Abstract: Structural health monitoring is widely applied in industrial sectors as it reduces costs associated with maintenance intervals and manual inspections of damage in sensitive structures, while enhanc...
TL;DR: It is concluded that the power spectrum blind sampling–based approach reduces effectively data transmission requirements in wireless sensor networks for operational modal analysis, without being limited by signal sparsity and without requiring a priori assumptions or knowledge of sign sparsity.
Abstract: This paper assesses numerically the potential of two different spectral estimation approaches supporting non-uniform in time data sampling at sub-Nyquist average rates (i.e., below the Nyquist frequency) to reduce data transmission payloads in wireless sensor networks (WSNs) for operational modal analysis (OMA) of civil engineering structures. This consideration relaxes transmission bandwidth constraints in WSNs and prolongs sensor battery life since wireless transmission is the most energy-hungry on-sensor operation. Both the approaches assume acquisition of sub-Nyquist structural response acceleration measurements and transmission to a base station without on-sensor processing. The response acceleration power spectral density matrix is estimated directly from the sub-Nyquist measurements and structural mode shapes are extracted using the frequency domain decomposition algorithm. The first approach relies on the compressive sensing (CS) theory to treat sub-Nyquist randomly sampled data assuming that the acceleration signals are sparse/compressible in the frequency domain (i.e., have a small number of Fourier coefficients with significant magnitude). The second approach is based on a power spectrum blind sampling (PSBS) technique considering periodic deterministic sub-Nyquist “multi-coset” sampling and treating the acceleration signals as wide-sense stationary stochastic processes without posing any sparsity conditions. The modal assurance criterion (MAC) is adopted to quantify the quality of mode shapes derived by the two approaches at different sub-Nyquist compression rates (CRs) using computer-generated signals of different sparsity and field-recorded stationary data pertaining to an overpass in Zurich, Switzerland. It is shown that for a given CR, the performance of the CS-based approach is detrimentally affected by signal sparsity, while the PSBS-based approach achieves MAC>0.96 independently of signal sparsity for CRs as low as 11% the Nyquist rate. It is concluded that the PSBS-based approach reduces effectively data transmission requirements in WSNs for OMA, without being limited by signal sparsity and without requiring a priori assumptions or knowledge of signal sparsity.
TL;DR: In this article, the electromechanical impedance-based damage identification approaches have shown excellent potential in identifying small-sized structural defects, while maintaining simplicity in implementation, in order to identify small-size structural defects.
Abstract: The electromechanical impedance-based damage identification approaches have shown excellent potential in identifying small-sized structural defects, while maintaining simplicity in implementation. ...