MULTILAYERED POLYMERIC FILM VIBRATIONS UNDER UN-SYMMETRICAL LOADING
Vibrations of a loaded multilayered polymeric film have been investigated numerically by assuming that the film consists of three layers. The upper and lower layers are stiff and do not deform in the transverse direction, while the internal layer can get deformed in that direction. The first eigenmodes are analysed and graphical findings of their investigation are presented. Experimental tests on the loaded multilayered polymeric material PET+PAP+LDPE (PET+PAP+LDPE denotes three-layered material made from PET – Poly-Ethylene Terephthalate, PAP – PAPer and LDPE – Low Density Poly-Ethylene) have been performed by exciting this material by forced vibrations. The first eigenmodes have been obtained by using the method of digital speckle photography, and it has been determined that eigenmodes change with the change of the excitation frequency. The obtained results of numerical investigations are compared with the experimental ones.The obtained study results are applied in determining the characteristics and qualities of packaging materials.