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You searched for subject:(Eigensystem Realisation Algorithm). One record found.

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University of New South Wales

1. Chowdhury, Mohammad Shakar. Application of System Identification using ERA/NExT for Damage Assessment in Composite Laminates.

Degree: Engineering & Information Technology, 2017, University of New South Wales

Polymer matrix composites are widely used in aircraft structures due to their superior specific stiffness and strength. However, laminated composites are susceptible to delaminations due to the low interlaminar fracture toughness of the matrix. Traditional NDI techniques for damage detection involve significant costs due to the requirement for the grounding of aircraft, shutdown time, and labour involved in inspections. Vibration monitoring for damage assessment in aircraft has several advantages such as being applicable in situ, not requiring external excitation and the potential for application as a continuous structural health monitoring system. Frequency monitoring is employed in modern aircraft for engine diagnostics and identification of major faults; however, when applied to structural components, monitoring frequency shifts only identifies the presence of damage but not its exact location and severity. Eigensystem Realization Algorithm (ERA) has been proposed for application to many structural components but not for assessment of delamination in composites.This thesis proposes the application of ERA coupled with Natural Excitation Technique (NExT) for delamination assessment in laminated composite structures, including stiffened composite panels. NExT provides the advantages that any type of excitation of the structure can be employed and the location of the excitation point need not be known. The algorithm for delamination assessment using ERA coupled with NExT was developed using Matlab code. The proposed method is first investigated and validated using transient vibration response generated by finite element simulation of composite laminates with delaminations. The simulated response is fed into the ERA/NExT algorithm to identify changes in the system parameters to estimate the location and reductions in bending stiffness in the damaged areas. The use of different types of excitation modes and excitations provided at different locations have been examined. Sensitivity analyses have been performed conducted study the influence of spacing of measurement points on the accuracy of delamination size and severity estimated using responses by numerical modelling of composite beams and laminated plates. The proposed method is validated experimentally with vibration measurements conducted on laminated carbon/epoxy beams, plates and stiffened panels with embedded delaminations and estimating the location, size and severity of the delaminations in the samples from the measured dynamic responses. Advisors/Committee Members: Shankar, Krishna, Engineering & Information Technology, UNSW Canberra, UNSW, Morozov, Evgeny, Engineering & Information Technology, UNSW Canberra, UNSW.

Subjects/Keywords: Eigensystem Realisation Algorithm; Vibration; Structural Health Monitoring; Natural Excitation Technique; Damage Assessment; Carbon Fiber Reinforced Polymer

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chowdhury, M. S. (2017). Application of System Identification using ERA/NExT for Damage Assessment in Composite Laminates. (Doctoral Dissertation). University of New South Wales. Retrieved from http://handle.unsw.edu.au/1959.4/57569 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:44102/SOURCE02?view=true

Chicago Manual of Style (16th Edition):

Chowdhury, Mohammad Shakar. “Application of System Identification using ERA/NExT for Damage Assessment in Composite Laminates.” 2017. Doctoral Dissertation, University of New South Wales. Accessed March 07, 2021. http://handle.unsw.edu.au/1959.4/57569 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:44102/SOURCE02?view=true.

MLA Handbook (7th Edition):

Chowdhury, Mohammad Shakar. “Application of System Identification using ERA/NExT for Damage Assessment in Composite Laminates.” 2017. Web. 07 Mar 2021.

Vancouver:

Chowdhury MS. Application of System Identification using ERA/NExT for Damage Assessment in Composite Laminates. [Internet] [Doctoral dissertation]. University of New South Wales; 2017. [cited 2021 Mar 07]. Available from: http://handle.unsw.edu.au/1959.4/57569 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:44102/SOURCE02?view=true.

Council of Science Editors:

Chowdhury MS. Application of System Identification using ERA/NExT for Damage Assessment in Composite Laminates. [Doctoral Dissertation]. University of New South Wales; 2017. Available from: http://handle.unsw.edu.au/1959.4/57569 ; https://unsworks.unsw.edu.au/fapi/datastream/unsworks:44102/SOURCE02?view=true

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