Imaging and Thickness Estimation of Fibre-Reinforced Polymers Using Ultrasonic Array Beamforming
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Glass fibre-reinforced polymer composites are often used in corrosive environments. However, the material can suffer from loss of mechanical durability as a result of an attack of the media. In order to protect the structural bearing laminate, the composites are segmented in different levels, the structural layer and the corrosion barrier layer, each containing a higher or lower percentage of glass fibre and thereby holds varying durability towards chemical attacks. This work applies the total focusing method, a delay-and-sum beamformer technique based on the full matrix capture, a routine that provides a complete set of time series from an array. Glass fibre-reinforced composites have directional dependent properties and high attenuation, complicating the modelling of ultrasonic propagation. In the project described in this thesis, pulse-echo measurement and phased arrays are used to estimate the thickness of the corrosion barriers, before and after, exposure to acid in high temperatures. A filter prior to imaging is designed to project the received phased array data onto a theoretical surface subspace. Experiments showed that the corrosion barrier thickness was measurable, when the laminas were sufficiently separated in the structural layer, no traces of the penetrated acid could be detected.
Place, publisher, year, edition, pages
2015. , 66 p.
Teknik, Ultrasound, Imaging, Thickness estimation, Beamfomring, Composites, Corrosion barrier, Total focusing method, Full matrix capture, Glass fibre
IdentifiersURN: urn:nbn:se:ltu:diva-57281Local ID: df800cc1-7598-4f8f-9e55-90406bac9c47OAI: oai:DiVA.org:ltu-57281DiVA: diva2:1030668
Subject / course
Student thesis, at least 30 credits
Engineering Physics and Electrical Engineering, master's level
Validerat; 20151104 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved