Numerical Study on the Effect of Gravity on Modal Analysis of Thin-Walled Structures

Summary Computational modal analysis is usually carried out without consideration of gravity forces. This is well motivated for many structures. However, the vibrational properties of thin-walled plane or shallow shell structures are very sensitive with respect to small modifications of the shell geometry and with respect to in-plane stress and reinforcement. One reason for these in-plane stresses and geometric modifications consists in gravity. This becomes an important issue when using test data obtained under the presence of gravity to update a simulation model where the influence of gravity is neglected. This study investigates the influence of gravity on the modal parameters of a thin rectangular plate and of a thin-walled cubic box. For that, di ff erent simulation models are used. While all of them utilize the finite element method, linear and non-linear approaches are compared. The latter take into account geometrical nonlinearities due to large deformations and the influence of gravity induced stress.