Nonlinear Membrane Direct and Inverse FEM Analysis

The analysis of thin structural components integrated within a general-purpose multibody system dynamics formulation is presented. An original inverse finite element solution procedure is developed to reconstruct the deformed shape of a membrane from in-plane membrane strain measurements, and eventually indirectly estimate the distributed loads. A direct solution approach is used in co-simulation with fluid-dynamics solvers to predict the configuration of the system under static and unsteady loads. Numerical validation of the inverse solution is performed considering the results of direct solution analysis. The direct and inverse solutions are validated considering experimental displacement and strain measurements obtained using digital image correlation. Moving Least Squares are used to smooth and remap measurements as needed by the inverse solution meshing. Utilizing surface strain measurements from strain sensors, the methodology enables the accurate computation of the three-dimensional displacement field.