Utilization of Optical Measurements and Thermography for Experimental Investigation of Oscillation Modes of a Slender Cantilever Beam

This article addresses the suitability of selected experimental methods for studying a slender cantilever beam periodically oscillating under forced excitation by an electromagnetic shaker. . The methods employed include laser Doppler vibrometry, high-speed optical and thermal imaging, complemented by a comparison with results obtained via X-ray computed tomography. The objective is to determine the body’s response to time-varying loads and to relate the temporal evolution of the applied force and inertia forces to the body’s shape change associated with a surface strain field. The experiments showed strong agreement between FEM-predicted and optically measured mode shapes, while long‑exposure high‑speed imaging produced envelopes comparable to tomographic projections. Thermographic measurements successfully captured the thermoelastic temperature field and enabled non-contact frequency identification, complementing laser Doppler vibrometry.