Inverse problems using spectral finite element method

Paunikar, S and Gopalakrishnan, S (2018) Inverse problems using spectral finite element method. In: 9th European Workshop on Structural Health Monitoring, EWSHM 2018, 10 - 13 July 2018, Manchester.

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Abstract

Aircraft structures in service are subjected to variety of forces which are omitted while designing the structure. Characterization of material properties of composites in service is complicated because of variations in orientation angles of each ply in a laminate. Identifying unaccounted forces and characterization of material properties non-destructively are termed as inverse problems, and are an important part of structural health monitoring. In this work, usefulness of spectral beam rod element for force reconstruction in wave propagation problems using spectral finite element method is demonstrated. Spectral finite element method (SFEM) for wave propagation, formulated in frequency domain, yields small system size as the input pulse and responses are directly related by the system transfer function. The exact interpolation functions used in SFEM generate algebraic system transfer functions making forward problem solving simpler and more accurate than finite element method. Force reconstruction requires measured experimental response. Finite element analysis was performed to generate surrogate experimental results which were used for force reconstruction using spectral beam rod element. Exponential interpolating functions for spectral beam rod element warrant the use of only one spectral beam rod element to model a crack free specimen. Using the same spectral element, it is also possible to formulate characterization problems as nonlinear minimization problem between experimentally observed response and response generated from forward SFEM solver.

Item Type:	Conference Paper
Publication:	9th European Workshop on Structural Health Monitoring, EWSHM 2018
Publisher:	NDT.net
Additional Information:	The copyright for this article belongs to the NDT.net.
Keywords:	Aircraft manufacture; Airframes; Algebra; Differential equations; Finite element method; Frequency domain analysis; Interpolation; Laminated composites; Structural health monitoring; Transfer functions; Wave propagation, Force reconstruction; Interpolating functions; Interpolation function; Nonlinear minimization; Properties of composites; Spectral finite element method; System transfer function; Wave propagation problems, Inverse problems
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	14 Aug 2022 06:02
Last Modified:	14 Aug 2022 06:02
URI:	https://eprints.iisc.ac.in/id/eprint/75737

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