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dc.contributorFaculty of Engineeringen_US
dc.creatorWei, Junhao-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/7501-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic University-
dc.rightsAll rights reserveden_US
dc.titleEvaluation of bolt looseness in bolted structures using nonlinearities of lamb wavesen_US
dcterms.abstractSteel bolt connections are widely used in engineering and industry manufacturing. Different loading conditions such as shock, vibration or transverse cyclic loading applied to structures result in stress concentration at screw bolts which may lead to looseness. Linear ultrasonic methods are general methods for Non-Destructive ultrasonic detection in varies of damages and defects which may however lose their effectiveness to the detection of looseness of bolts in the joint structures. For another, nonlinear guided waves are sensitive to microcracks, degradation, fatigue deformation and voids which can be applied on evaluating the looseness of bolts. Principle of detection with nonlinear Lamb wave is introduced first, to detect the presence of the fatigue damage and the location of the loosen bolt. Two rows of PZT transducers were placed to build up as a sensor network to actuate and receive the fundamental and second harmonic Lamb waves in the pitch-catch method. The approach successfully detected the presence of bolts’ looseness. Furthermore, a probability-based imaging algorithm was applied to reconstruct looseness area of the bolt.en_US
dcterms.extentxi, 86 leaves : ill. (some col.) ; 30 cm.en_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2014en_US
dcterms.educationalLevelAll Masteren_US
dcterms.educationalLevelM.Sc.en_US
dcterms.LCSHSteel, Structural -- Testing.en_US
dcterms.LCSHLamb waves.en_US
dcterms.LCSHBolts and nuts -- Testing.en_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.accessRightsrestricted accessen_US

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Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/7501