This paper presents the results of an experimental study of the parametric vibrations of a pulsating tensioned string. At certain amplitudes and frequencies of excitation in the form of a variable axial force, dynamic instability arises in the system, and transverse vibrations are excited. A non-contact measurement system based on high-speed cameras and an image analysis method was used for the measurements. The eigenfrequency values of the system were determined, and the different types of resonant vibrations arising were examined in detail. In each case, the mode shape of the vibrations, motion trajectories, time traces, spectra and phase portraits of the vibrations were studied. Vibrations in single-mode simple resonances with periodic type and in-plane motion, spatial non-periodic vibrations in combination resonances and also cases of very complex non-periodic vibrations with spatial motion when different types of parametric resonances excite simultaneously were identified.
