Pour savoir comment effectuer et gérer un dépôt de document, consultez le « Guide abrégé – Dépôt de documents » sur le site Web de la Bibliothèque. Pour toute question, écrivez à corpus@ulaval.ca.
 

Personne :
Zhang, Hai

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Zhang

Prénom

Hai

Affiliation

Université Laval. Laboratoire de vision et systèmes numériques

ISNI

ORCID

Identifiant Canadiana

ncf11735155

person.page.name

Résultats de recherche

Voici les éléments 1 - 10 sur 12
  • PublicationAccès libre
    Thermographic non-destructive evaluation for natural fiber-reinforced composite laminates
    (Basel : MDPI, 2018-02-05) Avdelidis, Nicolas P.; Zhang, Hai; Sarasini, Fabrizio; Maldague, Xavier; Santulli, Carlo; Ibarra Castanedo, Clemente; Sfarra, Stefano; Fernandes, Henrique
    Natural fibers, including mineral and plant fibers, are increasingly used for polymer composite materials due to their low environmental impact. In this paper, thermographic non-destructive inspection techniques were used to evaluate and characterize basalt, jute/hemp and bagasse fibers composite panels. Different defects were analyzed in terms of impact damage, delaminations and resin abnormalities. Of particular interest, homogeneous particleboards of sugarcane bagasse, a new plant fiber material, were studied. Pulsed phase thermography and principal component thermography were used as the post-processing methods. In addition, ultrasonic C-scan and continuous wave terahertz imaging were also carried out on the mineral fiber laminates for comparative purposes. Finally, an analytical comparison of different methods was given.
  • PublicationAccès libre
    Evaluation of the state of conservation of mosaics: Simulations and thermographic signal processing
    (Elsevier, 2017-04-13) Avdelidis, Nicolas P.; Zhang, Hai; Theodorakeas, Panagiotis; Maldague, Xavier; Ibarra Castanedo, Clemente; Perilli, Stefano; Sfarra, Stefano; Nardi, Iole; Koui, Maria
    Nondestructive inspection of mosaic structures is not a novelty in the thermographic scene. Interesting works can be retrieved from scientific literature, some of them dedicated to the use of static active configurations and/or the passive approach for the inspection of plastered mosaics or the assessment of mosaic floors. In the present study, a mosaic made by synthetic tesserae of different colors depicting a dove was inspected by active thermography using a static configuration. The mosaic was manufactured with artificial defects positioned at several depths and locations, where some of them, due to their dynamic nature, enabled the monitoring of their thermal effects over time. In particular, the mosaic contains: a void into which compressed air can be injected, a sponge insert that can be soaked by a known quantity of water through an external tube, and a sub-superficial recirculation circuit from which a stream of cold or hot water can flow. The variability of the nature of these defects, simulating what happens in a real case, was conveniently modeled by numerical simulation approaches. The latter point was assessed through the aid of a simulation software, while the comparison of the results obtained by numerical analysis with those derived by thermographic testing was also performed.
  • PublicationRestreint
    Evaluation of the state of conservation of mosaics : simulations and thermographic signal processing
    (Ed. scientifiques et médicales Elsevier, 2017-04-13) Avdelidis, Nicolas P.; Zhang, Hai; Theodorakeas, Panagiotis; Maldague, Xavier; Ibarra Castanedo, Clemente; Perilli, Stefano; Sfarra, Stefano; Nardi, Iole; Koui, Maria
    Nondestructive inspection of mosaic structures is not a novelty in the thermographic scene. Interesting works can be retrieved from scientific literature, some of them dedicated to the use of static active configurations and/or the passive approach for the inspection of plastered mosaics or the assessment of mosaic floors. In the present study, a mosaic made by synthetic tesserae of different colors depicting a dove was inspected by active thermography using a static configuration. The mosaic was manufactured with artificial defects positioned at several depths and locations, where some of them, due to their dynamic nature, enabled the monitoring of their thermal effects over time. In particular, the mosaic contains: a void into which compressed air can be injected, a sponge insert that can be soaked by a known quantity of water through an external tube, and a sub-superficial recirculation circuit from which a stream of cold or hot water can flow. The variability of the nature of these defects, simulating what happens in a real case, was conveniently modeled by numerical simulation approaches. The latter point was assessed through the aid of a simulation software, while the comparison of the results obtained by numerical analysis with those derived by thermographic testing was also performed.
  • PublicationAccès libre
    Non-destructive investigation of paintings on canvas by continuous wave terahertz imaging and flash thermography
    (Springer, 2017-04-05) Avdelidis, Nicolas P.; Fleuret, Julien; Saluja, Karan; Zhang, Hai; Peeters, Jeroen; Maldague, Xavier; Ibarra Castanedo, Clemente; Duan, Yuxia; Sfarra, Stefano; Fernandes, Henrique
    Terahertz (THz) imaging is increasingly used in the cultural heritage field. In particular, continuous wave (CW) and low frequency THz is attracting more attention. The first application of the THz technique inherent to the cultural heritage field dates back 10 years ago. Since 2006, tangible improvements have been conducted in the refinement of the technique, with the aim to produce clear maps useful for any art restorer. In this paper, a CW THz (0.1 THz) imaging system was used to inspect paintings on canvas both in reflection and in transmission modes. In particular, two paintings were analyzed: in the first one, similar materials and painting execution of the original artwork were used, while in the second one, the canvas layer is slightly different. Flash thermography was used herein together with the THz method in order to observe the differences in results for the textile support materials. A possible application of this method for the detection of artwork forgery requires some parameterization and analysis of various materials or thickness influence which will be addressed in a future study. In this work, advanced image processing techniques including principal component thermography (PCT) and partial least squares thermography (PLST) were used to process the infrared data. Finally, a comparison of CW THz and thermographic results was conducted.
  • PublicationRestreint
    Using through-transmission mid-wave infrared vision and air-coupled ultrasound for artwork inspection : a case study on mock-ups of Portrait of the Painter's Mother
    (INCOSE, 2020-03-01) Zhang, Hai; Maldague, Xavier; Osman, Ahmad; Ibarra Castanedo, Clemente; Sfarra, Stefano
    The conservation of artworks is playing an increasingly important role in society today. Non-destructive investigation can provide the potential to identify deterioration as early as possible. In this research, transmission mid-wave infrared (MWIR) vision and air-coupled ultrasound (ACU) were used to investigate two paintings on canvas made from different textile support materials. An X-ray technique was used in the work for validation. It was found that the transmission mode can probe deeper and the differences in absorption due to the different textile support materials can be distinguished. This paper summarises advantages of the transmission inspection mode and compares and analyses images from the two techniques from a physical point of view.
  • PublicationRestreint
    Impact modelling and a posteriori non-destructive evaluation of homogeneous particleboards of sugarcane bagasse
    (Springer, 2018-01-12) Mokhtari, Mohammed-Yacine; Avdelidis, Nicolas P.; Sarasini, Fabrizio; Zhang, Hai; Fiorelli, Juliano; Maldague, Xavier; Peeters, Jeroen; Ibarra Castanedo, Clemente; Sfarra, Stefano; Lucca Sartori, Diogo de; Perilli, Stefano; Tirillò, Jacopo
    With a view to gaining an in-depth assessment of the response of particleboards (PBs) to different in-service loading conditions, samples of high-density homogeneous PBs of sugarcane bagasse and castor oil polyurethane resin were manufactured and subjected to low velocity impacts using an instrumented drop weight impact tower and four different energy levels, namely 5, 10, 20 and 30 J. The prediction of the damage modes was assessed using Comsol Multiphysics ®. In particular, the random distribution of the fibres and their lengths were reproduced through a robust model. The experimentally obtained dent depths due to the impactor were compared with the ones numerically simulated showing good agreement. The post-impact damage was evaluated by a simultaneous system of image acquisitions coming from two different sensors. In particular, thermograms were recorded during the heating up and cooling down phases, while the specklegrams were gathered one at room temperature (as reference) and the remaining during the cooling down phase. On one hand, the specklegrams were processed via a new software package named Ncorr v.1.2, which is an open-source subset-based 2D digital image correlation (DIC) package that combines modern DIC algorithms proposed in the literature with additional enhancements. On the other hand, the thermographic results linked to a square pulse were compared with those coming from the laser line thermography technique that heats a line-region on the surface of the sample instead of a spot. Surprisingly, both the vibrothermography and the line scanning thermography methods coupled with a robotized system show substantial advantages in the defect detection around the impacted zone.
  • PublicationAccès libre
    Enhanced infrared image processing for impacted carbon/glass fiber-reinforced composite evaluation
    (Molecular Diversity Preservation International (MDPI), 2017-12-26) Avdelidis, Nicolas P.; Zhang, Hai; Osman, Ahmad; Maldague, Xavier; Ibarra Castanedo, Clemente; Sfarra, Stefano; Fernandes, Henrique; Matikas, Theodore E.
    In this paper, an infrared pre-processing modality is presented. Different from a signal smoothing modality which only uses a polynomial fitting as the pre-processing method, the presented modality instead takes into account the low-order derivatives to pre-process the raw thermal data prior to applying the advanced post-processing techniques such as principal component thermography and pulsed phase thermography. Different cases were studied involving several defects in CFRPs and GFRPs for pulsed thermography and vibrothermography. Ultrasonic testing and signal-to-noise ratio analysis are used for the validation of the thermographic results. Finally, a verification that the presented modality can enhance the thermal image performance effectively is provided.
  • PublicationRestreint
    Inspecting historical vaulted ceilings by means of physical and chemical analyses : an integrated approach combining active infrared thermography and reflectance spectroscopy
    (INCOSE, 2020-03-01) Zhang, Hai; Cheilakou, Eleni; Maldague, Xavier; Theodorakeas, Panagiotis; Ibarra Castanedo, Clemente; Sfarra, Stefano; Koui, Maria
    The present study discusses the experimental physicochemical results obtained from the historical vaulted ceilings of an ancient church located in central Italy. Infrared thermography (IRT) in the active configuration was used to map subsurface defects caused by a seismic event and to discover buried structures, while the visible and near-infrared (VIS-NIR) fibre optics diffuse reflectance spectroscopy (FORS) technique was applied to identify the pigments of wall paintings decorating the vault. Historical photographs are useful to readers in order to clarify the state of conservation before and after the earthquake that took place in 2009. The combination of the experimental results can be useful in restoration processes.
  • PublicationAccès libre
    Optical excitation thermography for twill/plain weaves and stitched fabric dry carbon fibre preform inspection
    (Pergamon Press, 2018-01-12) Zhang, Hai; Maldague, Xavier; Grosse, Christian U.; Ibarra Castanedo, Clemente; Robitaille, François; Ocana Martins, Jaime; Sfarra, Stefano
    Carbon fibres have become the natural choice as reinforcements for polymer composite materials (PMCs). The non-destructive inspection of dry carbon fibre preforms has the potential to increase the reproducibility and reduce the cost of PMC manufacturing, by identifying defects in dry multilayer preforms prior to resin injection. However, use of optical excitation thermography for inspecting dry carbon fibre preforms that constitute the structural reinforcement precursor in the manufacturing of PMCs is poorly documented in the open literature. In this work, optical excitation thermography was used for inspecting six dry multilayer carbon fibre preforms featuring different textile structures, thicknesses and defects, for the first time. Advanced image processing techniques were used in processing the thermographic data for comparative purposes. In particular, partial least square thermography, as a recently proposed technique, was studied in detail. Finally, the performance of different thermography techniques was analysed in terms of: 1) summarizing the capabilities of image diagnosis/processing techniques by signal-to-noise ratio analysis, and 2) identifying the monitoring modalities most suitable to industrial manufacturing.
  • PublicationAccès libre
    Eddy current pulsed thermography for ballistic impact evaluation in basalt-carbon hybrid composite panels
    (Optical Society of America, 2018-04-03) Zhang, Hai; Maldague, Xavier; Osman, Ahmad; Ibarra Castanedo, Clemente; Sarasini, Fabrizio; Sfarra, Stefano; Netzelmann, Udo; Perilli, Stefano
    In this paper, eddy current pulsed thermography was used to evaluate ballistic impact damages in basalt-carbon hybrid fiber-reinforced polymer composite laminates for the first time, to our knowledge. In particular, different hybrid structures including intercalated stacking and sandwich-like sequences were used. Pulsed phase thermography, wavelet transform, principle component thermography, and partial least-squares thermography were used to process the thermographic data. Ultrasound C-scan testing and X-ray computed tomography were also performed for comparative purposes. Finite element analysis was used for validation. Finally, an analytical and comparative study was conducted based on signal-to-noise ratio analysis.