?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F10632%2F&rft.title=Nondestructive+Evaluation+and+Structural+Health+Monitoring+Based+on+Highly+Nonlinear+Solitary+Waves&rft.creator=Ni%2C+Xianglei&rft.description=Recent+decades+have+witnessed+the+rapid+growth+and+acceptance+of+nondestructive+evaluation+(NDE)+techniques+in+assessment+of+infrastructures'+conditions.+Assessing+the+conditions+of+infrastructures+is+important+to+determine+their+safety+and+reliability+which+have+a+great+impact+on+today's+society.+The+existing+NDE+techniques+include+acoustics%2C+ultrasound%2C+radiology%2C+thermography%2C+electromagnetic+method%2C+optical+method%2C+and+so+on.+Properly+employed+NDE+techniques+can+reduce+the+maintenance+and+repair+cost+and+improve+the+reliability+of+the+infrastructures.%0D%0AIn+the+last+two+decades%2C+the+study+of+the+highly+nonlinear+solitary+waves+(HNSWs)+has+received+much+attention.+Most+of+these+studies+focused+on+the+propagation+of+HNSWs+in+granular+systems%2C+but+little+work+on+applications+of+HNSW-based+NDE+method+has+been+done.+HNSWs+are+mechanical+waves+that+can+form+and+travel+in+highly+nonlinear+systems%2C+one-dimensional+chain+of+identical+spheres+is+one+of+the+most+common+systems+that+can+support+the+generation+and+propagation+of+HNSWs.+In+the+study+presented+in+this+dissertation%2C+a+new+NDE+technique+based+on+the+generation+and+propagation+of+HNSWs+was+investigated+and+applied+to+different+structural+materials.%0D%0AFirst%2C+fundamental+research+on+the+generation+of+HNSWs+in+a+chain+of+stainless+steel+beads+by+laser+pulses+was+conducted.+The+results+showed+that+the+laser-based+generation+of+HNSWs+produces+results+that+are+equivalent+to+those+obtained+by+means+of+a+mechanical+striker.+Then%2C+the+feasibility+of+tuning+HNSWs+by+electromagnetically+induced+precompression+was+demonstrated+experimentally.+By+changing+the+precompression+on+the+chain+of+particles%2C+the+properties+of+the+HNSWs+could+be+tuned+in+a+wide+range.+Then+a+HNSW-based+transducer+was+designed+and+built.+The+transducer+was+remotely+and+automatically+controlled+by+National+Instruments+PXI+running+Labview.+The+ability+of+the+new+transducer+to+generate+repeatable+HNSWs+was+assessed.+Finally%2C+the+HNSW+transducer+was+used+to+monitor+cement+setting%2C+concrete+curing+and+epoxy+curing%2C+to+evaluate+the+bond+condition+of+an+aluminum+lap-joint%2C+and+to+detect+the+impact+damages+in+a+composite+plate.+The+results+showed+that+the+HNSW-based+technique+is+promising+for+structural+NDE.+A+pilot+numerical+study+on+acoustic+lens+which+is+a+device+can+focus+the+acoustic+waves+at+a+focal+point+was+also+conducted.&rft.date=2012-02-02&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F10632%2F1%2FPhD_dissertation_Xianglei_Ni_final.pdf&rft.identifier=++Ni%2C+Xianglei++(2012)+Nondestructive+Evaluation+and+Structural+Health+Monitoring+Based+on+Highly+Nonlinear+Solitary+Waves.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++