vibrometry

Vibrometry is the measurement of mechanical vibrations of objects, usually over a broad frequency range. It seeks to determine dynamic properties such as natural frequencies, damping, amplitude, and mode shapes, with minimal disturbance to the system. Vibrometry relies on sensing methods that convert mechanical motion into electrical or optical signals.

Methods are divided into contact and non-contact approaches. Contact methods attach sensors such as accelerometers or piezoelectric probes to the object. Non-contact techniques use light or fields; laser Doppler vibrometry measures surface velocity via Doppler shifts; laser interferometry and holographic vibrometry map displacement or full-field motion. Scanning probe variants offer high spatial resolution in microscopic or nanostructures.

Measurements typically include displacement, velocity, and acceleration as functions of time, from which frequency spectra, resonance peaks, damping, and mode shapes are derived. Data analysis commonly uses Fourier transforms, modal analysis, and comparisons with computational models such as finite element analyses.

Applications span structural health monitoring, non-destructive testing, materials science, MEMS and NEMS development, automotive and aerospace engineering, and instrument design. Vibrometry is also used in acoustics and musical instrument research.

Challenges include surface reflectivity and roughness, environmental noise, and alignment; calibration and reference standards are important. Developments in full-field and multi-axis vibrometry, higher sensitivity, and integration with simulations continue to expand capabilities.