Author: 周鴻儒Publisher:
ISBN:
Category :
Languages : en
Pages : 134
Book Description
Refinements on Resonant Ultrasound Spectroscopy for Measuring Viscoelastic Properties of Solids
Author: 周鴻儒Measurement of the Pressure Derivatives of Elastic Constants Using Resonance Ultrasound Spectroscopy
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 4
Book Description
Our primary goal is the measurement of the third order elastic constants of solids using resonance ultrasound spectroscopy (RUS). Progress on the construction of a new apparatus by which RUS measurements are made at elevated pressure is described. We chose materials which provide optimal values of alpha K sub tau for our initial set of measurements, and describe the relevant thermodynamic relations. Initial pressure runs with helium and argon pressurizing mediums for fused silica and KCl have been made, but their interpretation requires further analysis of the spectral data. Considerations regarding the measurement of third order elastic constants that are not obtained from purely hydrostatic stresses are presented. Completed RUS projects regarding the specimen size effects on measured elastic moduli, the elastic properties of Fe0.943O and the elastic/viscoelastic properties of iron are summarized. (MM).
Development of Resonant Ultrasound Spectroscopy for Determination of Material Properties of Solids at High Frequency
Author: 鄭鴻輝Viscoelastic Properties of Biological and High-damping Composite Materials
Author: Taeyong LeeResonant Ultrasound Spectroscopy for Elastic Constant Measurements
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Book Description
All objects exhibit vibrational resonances when mechanically excited. These resonant frequencies are determined by density, geometry, and elastic moduli. Resonant ultrasound spectroscopy (RUS) takes advantage of the known relationship between the parameters. In particular, for a freely suspended object, with three of the four parameters (vibrational spectra, density, geometry, or elastic moduli) known the remaining one can be calculated. From a materials characterization standpoint it is straight-forward to measure density and geometry but less so to measure all the elastic moduli. It has recently become possible to quickly and accurately measure vibrational spectra, and using code written at Los Alamos, calculate all the elastic moduli simultaneously. This is done to an accuracy of better than one percent for compression and 0.1 percent for shear. RUS provides rapid acquisition of materials information here-to-fore obtainable only with difficulty. It will greatly facilitate the use of real materials properties in models and thus make possible more realistic modeling results. The technique is sensitive to phase changes and microstructure. This offers a change to input real data into microstructure and phase change models. It will also enable measurement of moduli at locations in and about a weld thus providing information for a validating coupled thermomechanical calculations.
Resonant Ultrasound Spectroscopy of Solids
Author: Frank Arthur WillisPublisher:
ISBN:
Category : Resonant ultrasound spectroscopy
Languages : en
Pages : 298
Book Description
Analysis of Resonant Ultrasound Spectroscopy as a Technique to Evaluate Material Property Changes
Author: Gautham ManoharanPublisher:
ISBN:
Category :
Languages : en
Pages : 67
Book Description
The objective of this thesis is to validate Resonant Ultrasound Spectroscopy (RUS) as a non-destructive evaluation tool that can be used to study effects of radiation on the mechanical properties of a material, mainly its elastic constants. RUS involves experimentally measuring the resonant frequencies of a sample and calculating the elastic constants based on these measurements. Finite Element Method (FEM) is used to get the frequencies of the modes of free vibration for the sample model. This result depends on the elastic constant values used in the FEM simulation. Studies were conducted to confirm the accuracy of the FEM model, and determine the right configuration and parameters to use for the simulation. Assuming uniform and isotropic elastic property changes, the effects of radiation damage can be quantified by obtaining a set of matching resonant frequencies between the experimental and FEM simulation results, before and after irradiating the sample. This is done by adjusting the elastic constant values used in the simulation so that the results match with the experimentally obtained resonant frequencies. With powerful enough equipment, even real time monitoring is possible in harsh environments, thus pointing out imminent failure.
Elastic Properties of Novel Materials Using PVDF Film and Resonance Ultrasound Spectroscopy
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 120
Book Description
Elastic properties are of fundamental interest in condensed matter physics, material science, geoscience, and many branches of engineering. This paper describes the use of a relatively new technique, known as 'Resonant Ultrasound Spectroscopy' (RUS), with which the elastic properties of a small sample may be found in a single measurement, by analyzing a sufficient number of the sample's normal modes of free vibration. The present work describes the use of polyvinylidene (PVDF) thin-film transducers to extend the above method to very small -100 micrograms, fragile samples. The method is calibrated by measuring the elastic constants of a well-characterized material, cubic silicon. Measurements and analyses of several novel materials, including spherical ceramic particles ('proppants') and an aluminum alloy 'quasicrystal', are subsequently presented. Second-order perturbations of the normal mode frequencies due to minor sample preparation errors are also discussed.
Author: Guoxing Liu
Author: Hang Guo