Inverse internal pressure estimation of functionally graded cylindrical shells under thermal environment

The time-dependent pressure in long functionally graded cylindrical shells under thermal environment is estimated using the measured strains on their outer surfaces in conjunction with an inverse algorithm. The obtained strains from the solution of the related direct problem are used to simulate the data measurements. The direct problem is formulated based on the three-dimensional thermoelasticity theory under the plane strain conditions. The inverse solution procedure benefits from the discrepancy principle together with the conjugate gradient method as a powerful technique for optimization procedure. The differential quadrature method as an efficient and accurate numerical tool is employed to discretize the governing differential equations subjected to the related boundary and initial conditions in both spatial and temporal domains. The influence of measurement errors on the accuracy of the estimated internal pressure and also the displacement and stress components is investigated. The good accuracy of the results validates the presented approach.