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  • A mixed finite element base...
    Naskar, Sudipta; Banerjee, Biswanath

    International journal of mechanical sciences, 04/2021, Letnik: 196
    Journal Article

    •Proposal for full-field residual stress identification procedure from partially measured and corrupted measurement without eigenstrain information.•A mixed finite element approach, of Hellinger-Reissner type, is proposed within an inverse problem framework.•An energy based penalized least square approach is adopted to solve optimization problem.•Non-iterative reconstruction procedure is validated against a few problems of engineering interest. Display omitted In this paper a full-field residual stress identification procedure is proposed and explored from partially measured residual elastic strain or stress within a PDE constrained optimization framework. At first, we have constructed a penalized least-square cost functional with an appropriate regularization term. We have taken data discrepancy term in energy norm while the regularization term is a complementary strain energy functional. We then construct an appropriate Lagrangian to impose the optimization constraint. It turns out that using first order optimality condition leads to standard two field mixed, of Hellinger-Reissner type, variational formulation with residual stress and Lagrangian variable as independent field variables. This allows us to use standard two and three dimensional mixed finite elements for approximation of the stress and Lagrangian variable. Using mixed finite element set-up, we then solved these equations to obtain full-field residual stress distribution. One key issue of the proposed formulation, as in case of any inverse problem, is the choice of penalization parameter. In this context, we have used modified L-curve based approach to choose optimal penalty parameter. Finally, we assess the numerical effectiveness of the proposed procedure against a few problems of engineering interest.