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Quality assessment and damage detection in nanomodified adhesively-bonded composite joints using inkjet-printed interdigital sensors
摘要： In this work, the development of a planar interdigital capacitive sensor, directly onto the surface of a composite, for determining the initial quality of curing of bonded composite joints and assessing their long-term durability is presented. The sensor consisted of an interlocking comb-shaped array of silver electrodes and used to monitor the progress of cure of an adhesive resin and the subsequent damage state of the bond line in adhesively-bonded composite joints using impedance spectroscopy. The obtained results from the mechanical characterization indicated that the developed sensor did not affect the quality of the bondline while the added weight of the sensor is negligible. The curing process of the adhesive epoxy was successfully monitored while the ability of the sensor to assess the developed damage created by the mechanical loading was confirmed using transient infrared thermography.
关键词： quality assessment,inkjet printing,Bonded composite structures,damage detection,interdigital sensors
更新于2025-09-23 15:23:52
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Detection of damage of a filter by visualization of filtration process
摘要： This paper deals with testing of filters on the basis of visualization of filtration process. A filtration material can be damaged by flow of the filtered medium, high pressure drop and long-term adverse conditions. These negative effects can cause extensive damage of the filtration textile and filtration efficiency decreases. The filter can be also fractured during manufacturing, processing or by improper manipulation. A testing of a purposely damaged filtration textile is described in the article. Experiments were performed on the filtration setup which permits an optical entrance to the position where a sample of filter is placed. A laser sheet is directed into this place. Scattered light from seeding particles in front of and behind the filter is captured by a digital camera. Images from the camera are analyzed and the filtration efficiency versus time and also versus position can be obtained. Measuring chain including light scattering theory and measuring of light intensity by a digital camera are also discussed in the article.
关键词： damage detection,optical measurement,filtration,visualization,filtration efficiency
更新于2025-09-23 15:21:21
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Estimation of damage thickness in fibre-reinforced composites using pulsed thermography
摘要： Non-destructive-testing (NDT), including active thermography, has become an inevitable part of composite process and product verification, post-manufacturing. However, there is no reliable NDT technique available to ensure the interlaminar bond integrity during laminates integration, bonding or repair where the presence of thin airgaps in the interface of dissimilar polymer composite materials would be detrimental to structural integrity. This paper introduces a novel approach attempting to quantify the damage thickness of composites (the thickness of air gaps inside composites) through a single-side inspection of pulsed thermography. The potential of this method is demonstrated by testing on three specimens with different types of defect, where the Pearson Correlation Coefficients of the thickness estimation for block defects and flat-bottom holes are 0.75 and 0.85, respectively. This approach will considerably enhance the degradation assessment performance of active thermography by extending damage measurement from currently two dimensions to three dimensions, and become an enabling technology on quality assurance of structural integrity.
关键词： Active thermography,system identification,bonded repair,nonlinear correlation analysis,composite damage detection
更新于2025-09-23 15:21:01
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Detection of collapsed buildings due to the 2016 Kumamoto, Japan, earthquake from Lidar data
摘要： The 2016 Kumamoto earthquake sequence was triggered by an Mw 6.2 event at 21:26 on April 14. Approximately 28 hours later, at 1:25 on April 16, an Mw 7.0 event (the mainshock) followed. The epicenters of both events were located near the residential area of Mashiki town and the region nearby. Due to very strong seismic ground motion, the earthquake produced extensive damage to buildings and infrastructure. In this paper, collapsed buildings were detected using a pair of digital surface models (DSMs), taken before and after the April 16 mainshock by airborne light detection and ranging (Lidar) flights. Different methods for extracting the collapsed buildings from the data were evaluated, and the change of average elevations within a building footprint was found to be the most important feature. Finally, the distribution of collapsed buildings in the study area was presented, and the result was consistent with that of a building damage survey performed after the earthquake.
关键词： 2016 Kumamoto earthquake,Lidar,digital surface models,collapsed buildings,damage detection
更新于2025-09-23 15:19:57
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Detection of forest road damage using mobile laser profilometry
摘要： In this study, we tested the ability of mobile laser pro?lometry to quantify and compare forest road surface damage. We scanned a 1044 m long road, composed of six sections built from base aggregate layers with top layers constructed from various materials: section stabilized with Portland cement, an aggregate road with the Tensar SS 30 Geogrid, milled asphalt, milled construction waste with lime cover, aggregate section, section covered with sand. We used vehicle-mounted Roadscanner device to measure the road pro?les while driving on the road, which took 170 s. The device recorded 4000 points per one pro?le perpendicular to the driving direction, with measuring frequency 1–5 kHz. The width of the road was 4 m (resolution 1 mm). Individual pro?les were connected into a 3D pro?le with the help of an integrated inertial system. On each road section, the system recorded the number of damages (potholes, cracks), volume of individual damages (dm3), area of individual damages (dm2), and the mean and maximal depth of the individual damages (cm). After the scanning, we measured the same road sections manually with resolution 10 mm, which took 8 h. The total damage volume was 9.75/27.61 m3 (scanning/manually), with a total area of 241.4/1277.8 m2. It represented 5.8/30.6% of the road surface (4176 m2). We found the road sections evaluated as the most damaged in case of manual measurements were di?erent than the most damaged sections evaluated by scanning. We found statistically signi?cant differences between individual road sections only in cases of the depths and volumes of recorded damages.
关键词： Laser pro?lometry,Road surface,Forest roads,Damage detection
更新于2025-09-19 17:13:59
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Non-Contact Damage Detection under Operational Conditions with Multipoint Laservibrometry
摘要： Scanning laser–Doppler vibrometry (SLDV) can localize and visualize damages in mechanical structures. In order to enable scanning, it is necessary to repeat the vibration. Therefore, this technique is not suited to detect emerging hazards in working machinery that change the vibration behavior. A common technique for such cases is monitoring the vibration excited by machine operation with accelerometers. This technique requires mechanical coupling between sensors and the measurement object, which in?uences the high-frequency vibration responses. However, in the low-frequency range, local damages do not shift resonances or distort operational de?ection shapes (ODS) signi?cantly. These alterations in the vibration behavior are tiny and hard to detect. This paper shows that multipoint laservibrometry (MPV) with laser excitation can measure these e?ects e?ciently, and it further demonstrates that damages in?uence ODSs at frequencies above 20 kHz much stronger than at frequencies below 20 kHz. In addition, ODS-based damage indices are discussed; these are highly sensitive to minute visible changes of the ODSs. In order to enhance the sensitivity of hazard detection, the response vector assurance criterion value is computed and evaluated during operation. The capabilities and limitations of the methodology on the example of a cantilever with manually emerging damage are demonstrated.
关键词： structural health monitoring,multipoint laser-Doppler vibrometer,operational de?ection shape,operational condition,damage detection,laser–Doppler vibrometry,non-destructive testing,laser ablation
更新于2025-09-19 17:13:59
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Development of Smart Structure for Satellite Using Optical Fiber Sensors
摘要： 本開発では，はじめに，宇宙熱環境における太陽電池パネルの熱構造設計を地上試験で検証するため，光ファイバセンサを活用した健全性評価手法を開発した．本手法により，低温環境でのサブストレートのディンプル変形に起因するパネル内部の損傷発生を光ファイバセンサで検知できることを示した．次に，その開発技術を応用し，センサの着脱工程を削減して試験工期を短縮するため，光ファイバセンサ一体型衛星構造「スマート熱構造」の開発に取り組んだ．光ファイバ温度センサを開発し，数十点規模の温度センサとひずみセンサを備えた実験モデルを試作し，その製造性を確認した．また，その実験モデルを用いて，熱真空試験や四点曲げ試験を実施し，従来センサとほぼ同等の精度にて温度やひずみが計測できることを示した．さらに，スマート熱構造に搭載した電子機器内の部品にも温度センサを取り付けて動作試験を行い，従来では取得できなかった狭小部の温度も計測した．これらの結果から，スマート熱構造が実現可能であることを示した．
关键词： CFRP,Strain,Temperature,Multi-point measurement,Smart structure,Satellite,Optical fiber sensor,Damage detection
更新于2025-09-16 10:30:52
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Knowledge-Based Identification and Damage Detection of Bridges Spanning Water via High-Spatial-Resolution Optical Remotely Sensed Imagery
摘要： Bridges over water are important artificial objects that can be damaged by natural disasters. Accurate identification and damage detection of such bridges through the use of high-spatial-resolution optical remotely sensed imagery are important in emergency rescue and lifeline safety assessment. In this study, we detail a knowledge-based method of identification and damage detection of bridges spanning water using high-spatial-resolution optical remotely sensed imagery. Data on the body of water are extracted to define spatial extent and improve the timeliness of identification and damage detection, the threshold values of the rectangle degree and area are set to remove false bridge targets, and the damaged parts are detected according to the bridge’s rectangular characteristics and the relationship with the body of water. First, the characteristics, such as spectral, geometric, and textural, and spatial relationships of the bridge over water, are analyzed. Second, to limit the spatial extent of bridge identification and improve computational efficiency, data on the body of water are extracted. Third, the post-event bridge is identified from the viewpoint of bridge integrity based on shape and area parameters. Damage detection is then performed according to the bridge’s integrity. Finally, the results are evaluated for both non-positional and positional accuracy. Results of experiments carried out in Huiyang and Wenchuan, China, show that the proposed method, using high-spatial-resolution optical remotely sensed imagery, is effective for identification and damage detection of fallen and collapsed bridges spanning water. Therefore, the method is useful in updating the geographic database of bridges and assessing damage to them caused by natural disasters.
关键词： Bridges spanning water,High-spatial-resolution optical remotely sensed imagery,Feature knowledge,Feature analysis,Identification and damage detection
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [AIP Publishing LLC 41ST ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Volume 34 - Boise, Idaho (20–25 July 2014)] - Feasibility of PZT ceramics for impact damage detection in composite structures
摘要： Fiber reinforced plastic composites are becoming widely used in vehicles and airframe structures due to their high strength to weight ratio. However unlike metals, the multilayered composite structures are more susceptible to damage mechanisms such as disbonds and delaminations due to impacts. It is often dif?cult to visually detect the damage. Lead-Zirconate-Titanate (PZT) thin ?lms are becoming popular for in-situ structural health monitoring due to their small size, high piezoelectric coupling coef?cient, and ease of surface-mounting and/or embedding in composite structures. A network of such transducers could be utilized for damage detection using guided wave techniques, impedance techniques, or passive impact detection techniques. However, the PZT ?lms are subject to the same impact probabilities that the structure encounters. If the transducers fail due to the subjected impacts, they can result in false readings and ultimately failing to correctly detect damage in the structure. This paper presents a feasibility study using the guided wave S0 mode for detecting impact damage. The health of the structure is quanti?ed using guided wave measurements, and the PZT health is monitored using impedance methods.
关键词： impact damage detection,impedance techniques,PZT ceramics,composite structures,guided wave techniques
更新于2025-09-10 09:29:36
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Interfacial nanocomposite sensors (sQRS) for the core monitoring of polymer composites’ fatigue and damage analysis
摘要： The quick development of the smart factory and prognostic and health management (PHM), in the fields of aeronautic, automotive and green energies, is evidencing a need for sensors able to monitor the behavior of composite materials all along their life at the closest of the matter. In situ fabricated conductive polymer nanocomposite (CPC) sensors are bringing an interesting solution to this prospect as they can be integrated homogeneously in the core of composites to probe their deformations and damage. In particular fatigue which is one important mode of failure of polymer composites can be monitored from early signs of damage until the final breakage by analyzing the piezo-resistive response of quantum resistive strain sensors (sQRS) made of carbon nanotubes. We have developed all these aspects in the paper taking the example of a classical glass fibers/epoxy composite instrumented in its core with two sQRS to monitor its short and long term fatigue behavior.
关键词： damage detection,fatigue,structural health monitoring,Piezo-resistive strain sensors,conductive polymer nanocomposites,carbon nanotubes,polymer composites
更新于2025-09-10 09:29:36