The influence of stiffened plate modifications on the energy balance

The change in plate stiffness introduced by a system of stiffeners slightly changes the whole system mass and results in a significant change in natural frequencies, distribution and values of vibrational energy. Stiffeners can be treated as an additional subsystem that not only changes the plate stiffness but also accumulates and dissipates a part of vibrational energy. The energy balance analysis of a stiffened plate was carried out for a plate treated as an assembly of a homogeneous plate and a system of beams. On the basis of modal participation factors the energies dissipated in plates and system of stiffeners were determined. The natural frequencies and modal participation factors were computed as a solution of an unconstrained optimization problem by the use of the Nelder Mead optimization algorithm and compared to a twice faster genetic algorithm. Theoretical computations of a homogeneous plate and stiffeners energies were verified by energy distribution carried out on the basis of frequency respo...