Modified constitutive relation error for field identification: Theoretical and experimental assessments on fiber orientation identification in a composite material

This article addresses the application of the modified constitutive relation error to field identification problems in the framework of elastostatics. We show how relevant is the addition of a gradient‐penalizing regularization term (in normL 1orL 2), and emphasize the role played by unreliable boundary conditions. This leads to the proposition of a method using two parameters, for which automatic determination is addressed. All theoretical assessments are illustrated on experimental data. The test‐problem consists in the identification of the heterogeneous fiber‐orientation in a woven fabric composite from a unique quasi‐static tensile test with digital image correlation.