Development Of High-Resolution Mechanical Spectroscopy, HRMS: Status And Perspectives. HRMS Coupled With A Laser Dilatometer

Archives of Metallurgy and Materials

L.B. Magalas¹ 

[1] AGH UNIVERSITY OF SCIENCE AND TECHNOLOGY, FACULTY OF METALS ENGINEERING AND INDUSTRIAL COMPUTER SCIENCE, AL. MICKIEWICZA 30, 30-059 KRAKÓW, POLAND;

关键词: Keywords: mechanical spectroscopy;    internal friction;    elastic modulus;    noise;    Fourier transform;    Hilbert transform;    joint-time frequency analysis;    dilatometry;   

DOI  :  10.1515/amm-2015-0350

学科分类：金属与冶金

来源: Akademia Gorniczo-Hutnicza im. Stanislawa Staszica / University of Mining and Metallurgy

【 摘 要 】

Recent achievements in the development of low-frequency high-resolution mechanical spectroscopy (HRMS) are briefly reported. It is demonstrated that extremely low values of the loss angle, ϕ, (tanϕb = 1×10−5) can be measured as a function of frequency, and the precision in estimation of the dynamic modulus is better than 1×10−5 in arbitrary units. Three conditions must be fulfilled to obtain high resolution in subresonant and resonant mechanical loss measurements: (1) noise in stress and elastic strain signals must be lower than 70 dB, (2) high quality of stress and strain signals must be tested both in the frequency- and time-domains, and (3) the estimation of the mechanical loss and modulus must be verified by at least two different computing methods operating in the frequency- and time-domains. It is concluded that phase measurements in the subresonant domain are no longer determined by precision in estimation of the loss angle. Recent developments in high-resolution resonant mechanical loss measurements stem from the application of advanced nonparametric and parametric computing methods and algorithms to estimate the logarithmic decrement and the elastic modulus from exponentially damped free decaying oscillations embedded in experimental noise.

【 授权许可】

Unknown