Residual stress identification in thin plates based on modal data and sensitivity analysis. (1st February 2022) - Huang, Ce
Abstract: Residual stresses commonly arise in manufacturing, rolling, welding and heating of mechanical structures and they have a critical influence on fatigue strength, creep resistance and other properties of the structures. Therefore, identifying the residual stress distribution is crucial for quality assessment of these structures. To this end, this paper proposes a new non-destructive residual stress identification approach for thin plates using modal data. There are two key ingredients in establishing the proposed approach. The first is the parameterization of residual stress field by resorting to the Airy stress function so that residual stress identification is recast as a parameter identification problem. The second lies in the inverse identification of stress parameters through a sensitivity-based procedure. In doing so, stress parameter identification is formulated as a nonlinear optimization problem whose goal function is just least-squares of the misfit between the measured and calculated data, and then, modal sensitivity analysis and the trust-region constraint are introduced to iteratively get the solution. Numerical examples are conducted to verify the feasibility and accuracy of the proposed approach. Highlights: A new non-destructive sensitivity-based approach is proposed for residual stress identification of thin plates. The Airy stress function is used to parameterize the self-equilibrating residual stresses. The trust-region constraint is introduced to enhance the convergence. The proposed approach is found able to identify the residual stresses for plates of various shapes from noised modal data.