From Ultrasound to Audible: A Small Journey through Acoustic Emission and Noise from Tribological and Mechanical Systems

Description

Understanding friction, wear, and other mechanical stresses from the microscopic scale upwards is fundamental to improving the reliability, efficiency, and sustainability of modern mechanical systems. This talk focuses primarily on ultrasonic acoustic emission signals in the 50 kHz–2 MHz range, complemented by an outlook on current research in the hearable frequency range. Ultrasonic emissions predominantly arise from tribological contacts such as journal bearings, valvetrain components, cylinder surfaces, and gears. Well‑defined quantitative relationships link these emission features to microscopic friction mechanisms, wear processes, and lubricant degradation —addressing several limitations inherent to conventional vibration‑based diagnostics.
This methodology not only enables the early detection of incipient faults, but also informs targeted strategies for noise and wear reduction. A consistent, cross‑referenced acoustic database—covering diverse tribological configurations, materials, and lubricants—facilitates comparative and generalizable analyses. Advanced signal‑processing techniques, ranging from classical time‑domain evaluations to spectral and time‑frequency decomposition, yield composite diagnostic parameters that enhance interpretability.
Machine‑learning models trained on acoustic data reveals otherwise unknown information in the signals, giving one the ability to predict friction power, differentiate particle friction modes, and estimate surface roughness, to name only a few. The integration of these methods in classical mechanical vibration analysis opens new possibilities for real‑time process control, lubricant condition monitoring, and intelligent mitigation approaches such as predictive maintenance and active compensation. Ultimately, these advances support extended component service life, reduced acoustic emissions, and the development of environmentally sustainable tribological systems.

Period	14 Oct 2025
Event title	Smart Actuators Day 2025
Event type	Conference
Location	Linz, AustriaShow on map
Degree of Recognition	International