Vibration of a bimodulus thick plate

Natural vibrations of a simply supported rectangular bimodulus thick plate subjected to a combination of pure bending stress and extensional stress in the plane of the plate is investigated. The governing equations obtained using the average stress method are sovled in exact form. The natural frequencies are compared with the previous results of the authors for ordinary thick plates, and with the neutral surface locations and natural frequencies ofbimodular plates without initial stress. New results are presented for natural frequencies of bimodular plates with initial stress. The effects of various parameters on the natural frequencies are studied.