Full-Field Strain Reconstruction Using Uniaxial Strain Measurements: Application to Damage Detection

Abstract

This work investigates the inverse problem of reconstructing the continuous displacement field of a structure using a spatially distributed set of discrete uniaxial strain data. The proposed technique is based on the inverse Finite Element Method (iFEM), which has been demonstrated to be suitable for full-field displacement, and subsequently strain, reconstruction in beam and plate structures using discrete or continuous surface strain measurements. The iFEM uses a variationally based approach to displacement reconstruction, where an error functional is discretized using a set of finite elements. The effects of position and orientation of uniaxial strain measurements on the iFEM results are investigated, and the use of certain strain smoothing strategies for improving reconstruction accuracy is discussed. Reconstruction performance using uniaxial strain data is examined numerically using the problem of a thin plate with an internal crack. The results obtained highlight that strain field reconstruction using the proposed strategy can provide useful information regarding the presence, position, and orientation of damage on the plate.

Special Issue on Novel Approaches for Structural Health Monitoring

“…The accurate full-field reconstruction of the strain and displacement fields of a structure using a set of uniaxial strain measurements is the prime focus of the work presented in [2]. The use of uniaxial strain measurements, as obtained from a fibre-optic sensor, for two-dimensional displacement field reconstruction leads to difficulties due to insufficient strain information at a point and can potentially lead to a breakdown of the reconstruction procedure.…”

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

“…The iFEM has been successfully applied to the monitoring of a container ship [ 19 , 20 ], wind turbines [ 21 , 22 ], and to complex aeronautical structures [ 23 ]. Colombo et al in [ 24 ] developed an iFEM-based damage detection methodology, and current research is expanding towards damage identification and quantification [ 25 , 26 , 27 , 28 ]; very recent developments are in the direction of a non-deterministic displacement reconstruction [ 29 ].…”

Structural Deformation Reconstruction Using the Hybrid Shell-Beam Inverse Finite Element Method: Experimental Application on a Thin-Walled Stiffened Panel

“…The reconstruction of the displacement field from discrete strain sensors is defined as shape sensing. The shape sensing methods represent an important tool to improve the efficiency of the structural maintenance operations [2] and can also be implemented for damage detection activities [3,4]. Among the existing approaches, the inverse Finite Element Method (iFEM) has emerged has one of the most accurate and efficient [5].…”