Improving resonant frequency and damping analysis at high temperatures via laser Doppler vibrometer sensor

Abstract A common challenge in materials science is the accurate characterization of thermomechanical properties at high temperatures, particularly when significant microstructural changes and high damping affect the materials’ response. Such phenomena are characteristic in refractory materials which are, commonly, heterogeneous and multi-component in nature. This work addresses these limitations by progressively extending the operational boundaries of the resonant frequency and damping analysis via the impulse excitation technique. A typical electret (an acoustic sensor) is compared with an advanced laser Doppler vibrometer (LDV; an optical sensor) for the characterization of different refractory materials of increasing complexity. The LDV setup provides robust, continuous measurements even through intense microstructural events associated with high damping, such as liquid phase formation, reactive sintering, phase transformation, and microcrack formation. This advancement offers the clarity needed to directly link microstructural phenomena with material performance, bridging a critical gap between fundamental research and industrial design.