Abstract:
Nowadays, the use of composite materials has taken a large place in civilian industries as well
as in military and aerospace industries. In particular, composite structures with one or more
attachments, such as different types of sensors, are often encountered in engineering
applications. These attached masses affect the dynamic responses of the main structures.
Therefore, the present thesis addresses the effect of attached mass on dynamic properties of
composite laminate and sandwich plates, under flexural vibration, for clamped-free-free-free
boundary conditions. Furthermore, factors influencing the effect of attached mass on the
natural frequencies of laminate composite are studied using the Taguchi method. The
considered factor parameters are: attached mass weight, attached mass locations from the
clamped edge, staking sequences, and number of layers. In addition, the effects of the
attached mass on the natural frequencies of sandwich plate according to several factors , these
factors are the positions of the attached mass, the mechanical characteristics of the core, the
ratios of thickness of core/ thickness the plate (hc / h), and the length / width ratios of the
plate (a / b)). So, the study carried out is based on a model of calculation by the use of the
finite element method. The results of this study indicate that the dynamic characteristics of the
laminate composite and sandwich plates are sensitive to the attached mass, where the natural
frequencies are found to be inversely proportional to the mass weight. The results were found
that the locations of the attached mass are the most important factors affecting the natural
frequencies of laminate plate, where the location of the masses fell into the antinodes area of
vibration.
