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 - 5 sur 5
  • 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.
  • 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.
  • 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.
  • 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.
  • PublicationRestreint
    Non-destructive imaging of marqueteries based on a new infrared-terahertz fusion technique
    (Pergamon, 2022-06-25) Avdelidis, Nicolas P.; Hu, Jue; Zhang, Hai; Gargiulo, Gianfranco; Maldague, Xavier; Sfarra, Stefano; Zhang, Mingli; Yang, Dazhi
    Detection of subsurface defects has hitherto been regarded as an important element in the course of preserving cultural heritage. To do so, non-destructive imaging approaches for viewing and determining the location of splitting inside the sample under test are required, which constitute the subject of the present study. Both active thermography and terahertz imaging have demonstrated their potential in providing non-destructive inspection on cultural heritage objects. Conventionally, active thermography has been used to retrieve details on the defects as well as morphological data from the surface and subsurface, whereas pulsed terahertz imaging has been applied to record the internal material distribution. Here, the feature extraction, selection and fusion framework is extended to design a fusion process to merge the information obtained by both active thermography and terahertz imaging; in this way, the technique naturally inherits the strengths of both aforementioned imaging technologies. The fusion technique is able to produce images with high-contrast defect information located at different depths. To demonstrate the efficacy of the suggested technique, an experiment has been conducted on an ancient marquetry.