Experimental validation of the spectral criterion for the diagnosis of periodic rod structures using ferroelectric strain gauges

Successive impact excitation and construction of Fourier transforms of linear and nonlinear strain responses and phase portraits of undamaged or damaged vertically suspended models of a periodic welded rod structure were used to establish the dependence of the area ratio of the phase portraits of the nonlinear and linear domains of the strain response, which characterizes the stress (damage) of the model, on the impact momentum. The dynamic strain responses were recorded using ultra-wideband ($10^{-2}\div10^8$ Hz) ferroelectric microgauges based on thin $\mathrm{Pb}(\mathrm{Zr}_{0.53}\mathrm{Ti}_{0.47})\mathrm{О}_3$ films $2\mu$m in thickness with a $0.8$ mm$^2$ contact area.