Shape sensing and damage identification with iFEM on a composite structure subjected to impact damage and non-trivial boundary conditions

Shape Sensing of a Complex Aeronautical Structure with Inverse Finite Element Method

“…Model definition is one of the most challenging tasks for both direct and inverse FEM, in particular when dealing with non-trivial geometries and boundary conditions. The linear superimposition of effects with iFEM has been still introduced in [ 37 ], weighting the contribution of different iFEM elementary models to better approximate the reference displacement field. In particular, the elementary models must have the same geometrical discretization, i.e., the same nodes and elements, while different boundary conditions can be applied to better model non-trivial constraints.…”

“…Then, other formulations exploit a combined use of iFEM and the Refined Zig-Zag theory (RZT) to compute the through-the-thickness displacement field on composite structures [ 34 , 35 ], while, the combination of isogeometric analysis and iFEM is beneficial for large non-linear deformations [ 36 ]. Finally, the iFEM was also recently extended to damage identification [ 30 , 37 , 38 , 39 ] by considering that discrepancies between the physical structure and the iFEM model generate wrong displacement and strain field reconstructions.…”

“…The whole procedure is assessed with both a numerical and experimental application, assessing the iFEM strain reconstruction also far from the input sensors and in presence of complex displacement and strain fields. In particular, limitations on the number and locations of input sensors, acquired by a LUNA ODISI-B system, impose different model simplifications, which are compensated by the linear superimposition of two different iFEM models, as already proposed by the authors in [ 37 ], accounting for the actual stiffness of the boundary constraints. Furthermore, the adopted sensor technology limits the acquisition to a single strain component at each measurement location, resulting in a partial definition of the input strain field, where most of the measures are aligned with the load direction, few measurements are transversal to the load direction, and no measurements are available for the shear strain component.…”

Damage Identification and Quantification in Beams Using Wigner-Ville Distribution

“…A similar approach was also used by the authors of [ 25 , 26 , 27 , 28 ]. The improved version of this approach was reported by the authors of [ 29 , 30 ], where the adaptive baseline concept was proposed. These approaches, however, did not guaranteed proper localization and identification of small damage, which is essential in demanding NDT and SHM applications.…”

Numerical and experimental verification of an inverse‐direct approach for load and strain monitoring in aeronautical structures

“…Some 17–19 exploit regressions between the excitation source and some residuals to identify the load but suffer from computational resources demand when a high number of degrees of freedom is present in the considered structure. Others, 20–24 falling under the category of shape sensing, aim at reconstructing the full displacement and thus, strain, fields of a structure based on a least‐squares minimization of an error functional defined as a comparison between discrete strain measurements and a numerical formulation of the same without requiring any a priori knowledge of the load boundary condition and the material properties. However, the latter are limited to date to plates and beam‐like structures discretized with inverse finite elements method (iFEM).…”