Shape Sensing of Stiffened Plates Using Inverse FEM Aided by Virtual Strain Measurements

Roy, Rinto; Esposito, Marco; Surace, Cecilia; Gherlone, Marco; Tessler, Alexander

doi:10.1007/978-3-031-07254-3_46

Cited by 2 publications

(3 citation statements)

References 8 publications

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“…The success of these investigations has also prompted the use of iFEM for SHM applications, specifically for damage detection in metallic [38,39] and composite [40][41][42] structures, and more recently for damage prognosis [43,44]. A key limitation of the 2D iFEM is the need for a large number of strain measurements to generate accurate results, which can be resolved using an optimal selection of sensor locations [45][46][47] and strain pre-extrapolation to produce virtual measurement sites [48][49][50][51].…”

Section: Introductionmentioning

confidence: 99%

Hybrid Shell-Beam Inverse Finite Element Method for the Shape Sensing of Stiffened Thin-Walled Structures: Formulation and Experimental Validation on a Composite Wing-Shaped Panel

Esposito

Roy

Surace

et al. 2023

Sensors

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This work presents a novel methodology for the accurate and efficient elastic deformation reconstruction of thin-walled and stiffened structures from discrete strains. It builds on the inverse finite element method (iFEM), a variationally-based shape-sensing approach that reconstructs structural displacements by matching a set of analytical and experimental strains in a least-squares sense. As iFEM employs the finite element framework to discretize the structural domain and as the displacements and strains are approximated using element shape functions, the kind of element used influences the accuracy and efficiency of the iFEM analysis. This problem is addressed in the present work through a novel discretization scheme that combines beam and shell inverse elements to develop an iFEM model of the structure. Such a hybrid discretization paradigm paves the way for more accurate shape-sensing of geometrically complex structures using fewer sensor measurements and lower computational effort than traditional approaches. The hybrid iFEM is experimentally demonstrated in this work for the shape sensing of bending and torsional deformations of a composite stiffened wing panel instrumented with strain rosettes and fiber-optic sensors. The experimental results are accurate, robust, and computationally efficient, demonstrating the potential of this hybrid scheme for developing an efficient digital twin for online structural monitoring and control.

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Section: Introductionmentioning

confidence: 99%

Hybrid Shell-Beam Inverse Finite Element Method for the Shape Sensing of Stiffened Thin-Walled Structures: Formulation and Experimental Validation on a Composite Wing-Shaped Panel

Esposito

Roy

Surace

et al. 2023

Sensors

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“…Strain pre-extrapolation techniques interpolate or extrapolate the measurements on the top and bottom of the shell in the elements missing experimental measurements before the iFEM computes the displacement field; this solution has been proven to increase the accuracy of the iFEM methods and to reduce the number of sensors required to achieve a prescribed performance [ 33 , 34 , 36 ]. Any interpolation/extrapolation method may be employed in principle; the state-of-the-art employs the SEA, modal expansion [ 37 ], and physics-based pre-extrapolation techniques [ 38 ], although polynomial fittings may be robust enough for simpler case studies. It should be noted that the pre-extrapolated values do not have to be exactly equal to the true values that would be measured by sensors since weights may alleviate this discrepancy [ 33 , 34 ], and the displacement field reconstructed by the iFEM restores the compatibility in the displacement field.…”

Section: Introductionmentioning

confidence: 99%

“…It should be noted that the pre-extrapolated values do not have to be exactly equal to the true values that would be measured by sensors since weights may alleviate this discrepancy [ 33 , 34 ], and the displacement field reconstructed by the iFEM restores the compatibility in the displacement field. The interested reader may refer to [ 33 ] for a comparison of the SEA and polynomial fittings as strain pre-extrapolation techniques, while the SEA and modal expansion methods are explored in [ 37 ].…”

Section: Introductionmentioning

confidence: 99%

Variable Thickness Strain Pre-Extrapolation for the Inverse Finite Element Method

Poloni

Oboe

Sbarufatti

et al. 2023

Sensors

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The inverse Finite Element Method (iFEM) has recently gained much popularity within the Structural Health Monitoring (SHM) field since, given sparse strain measurements, it reconstructs the displacement field of any beam or shell structure independently of the external loading conditions and of the material properties. However, in principle, the iFEM requires a triaxial strain measurement for each inverse finite element, which is seldom feasible in practical applications due to both costs and cabling-related limitations. To alleviate this problem several techniques to pre-extrapolate the measured strains have been developed, so that interpolated or extrapolated strain values are inputted to elements without physical sensors: the benefit is that the required number of sensors can be reduced. Nevertheless, whenever the monitored components comprise regions of different thicknesses, each region of constant thickness must be extrapolated separately, due to thickness-induced discontinuities in the strain field. This is the case in many practical applications, especially those concerning fiber-reinforced composite laminates. This paper proposes to extrapolate the measured strain field in a thickness-normalized space, where the thickness-induced trends are removed; this novel method can significantly decrease the number of required sensors, effectively reducing the costs of iFEM-based SHM systems. The method is validated in a simple but informative numerical case study, highlighting the potentialities and benefits of the proposed approach for more complex application scenarios.

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Shape Sensing of Stiffened Plates Using Inverse FEM Aided by Virtual Strain Measurements

Cited by 2 publications

References 8 publications

Hybrid Shell-Beam Inverse Finite Element Method for the Shape Sensing of Stiffened Thin-Walled Structures: Formulation and Experimental Validation on a Composite Wing-Shaped Panel

Hybrid Shell-Beam Inverse Finite Element Method for the Shape Sensing of Stiffened Thin-Walled Structures: Formulation and Experimental Validation on a Composite Wing-Shaped Panel

Variable Thickness Strain Pre-Extrapolation for the Inverse Finite Element Method

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