Dynamic response obtained by direct numerical integration for pre-deformed rectangular plates subjected to in-plane loading

The dynamic response of imperfect (initially deformed) rectangular plates has been previously investigated both experimentally and theoretically. The theoretical approach used was an asymptotic method that required simplifying assumptions. To eliminate the need for these assumptions, a direct integration approach has been used. The results confirm the asymptotic method results on the modal interaction between forced and parametric resonances, explain experimental results on the modal interaction between resonances of the same nature (forced-forced and parametric-parametric) and show the existence of coalescence phenomena (two different modes vibrating at the same frequency), with the particular characteristic that the dominating mode transfers energy to the one outside its instability zone. (C) 1996 Academic Press Limited