dynamic analysis of sandwich constructions using a modal method

in this paper dynamic analysis (modal-method) of sandwich contructions have been studied. for this purpose a computer program was developed that could analyse the sandwich construction's dynamics. by using the program, one can find the natural frequencies, the normal modes and dynamic response of the free and forced vibrations.by solving few problems in this article, we have illustrated the effects of the lumped mass method, boundary conditions and the types of element, on the natural frequencies of the sandwich beams and plates. finally, natural frequecy of the sandwiched plate has been compared to the natural frequency of a homogeneous plate of the same weight which is made of the face plate material.