Determination of the product of inertia of stiffened plates based on Finite Element Method results

In this work, the computational program EUREQA is used to find analytical models for the adjustment of an existing equation used to calculate the improvement of the inertia moment on a ribbed part in relation to the same object, but unribbed. There is some divergence between the analytical and the numerical results using the classical Orlov's equation. The aim of the work is to develop an analytical model, based on Orlov's one, in order to improve the accuracy of the results. Two ribbed plate FEM models, having four ribs along all length were built in ANSYS, one used solid, and the other shell elements. The inertia moment was calculated analytically using Orlov's expression and was collected from the FEM models on ANSYS. Therefore, using relevant geometric variables, in this case, and, it was possible, resorting to the computation program EUREQA, to find equations that adjust the initial equation presented by Orlov. The models are proven to be accurate in the prediction of the improvement of the inertia moment when ribs are added to a structure, and are generalized to be possible to be applied to any ribbed structure having ribs of equal dimensions.