Ultrasonic determination of the elastic properties and their pressure and temperature dependences in very denseYBa2Cu3O7−x

1992 ◽  
Vol 46 (2) ◽  
pp. 1157-1165 ◽  
Author(s):  
M. Cankurtaran ◽  
G. A. Saunders ◽  
K. C. Goretta ◽  
R. B. Poeppel
Keyword(s):  
Elastic Properties ◽  
Temperature Dependences ◽  
Ultrasonic Determination

Accuracy of Elastic Property Measurement in Mandibular Cortical Bone is Improved by Using Cylindrical Specimens

2002 ◽  
Vol 124 (6) ◽  
pp. 714-723 ◽  
Author(s):  
C. L. Schwartz-Dabney ◽  
P. C. Dechow
Keyword(s):  
Cortical Bone ◽  
Elastic Properties ◽  
Specimen Thickness ◽  
Velocity Measurements ◽  
Ultrasonic Velocities ◽  
Lack Of Information ◽  
Ultrasonic Determination ◽  
Property Measurement ◽  
Cylindrical Samples

Ultrasonic determination of elastic properties in human craniofacial cortical bone is problematic because of a lack of information about the principal material axes, and because the cortex is often thinner than in long bones. This study investigated solutions that permit reasonable determination of elastic properties in the human mandible. We tested whether ultrasonic velocities could be reliably measured in cylindrical samples of aluminum and mandibular bone, and the effects of reduced specimen thickness. Results indicted that (1) varying shape had minimal effects on ultrasonic velocities or derived elastic properties, and (2) ultrasonic velocities have relatively increased measurement error as propagation distances decreased. The increased error in velocity measurements of mandibular cortical specimens of less than 1.2 mm in thickness should be considered when assessing the reliability of single measurements.

scholarly journals A parametric prediction of the Young’s modulus of polymers enhanced with ΜWCNTs

2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Experimental Results ◽  
Scale Model ◽  
Fe Model ◽  
Multi Scale ◽  
Unit Cells ◽  
Random Dispersion

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.

scholarly journals Enhancement of a New Methodology Based on the Impulse Excitation Technique for the Nondestructive Determination of Local Material Properties in Composite Laminates

2020 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Carlo Boursier Niutta
Keyword(s):  
Resonant Frequency ◽  
Elastic Properties ◽  
Composite Laminates ◽  
Concentrated Mass ◽  
Modal Shape ◽  
Nondestructive Determination ◽  
Material Orientation ◽  
Impulse Excitation ◽  
Clamping System

A new approach for the nondestructive determination of the elastic properties of composite laminates is presented. The approach represents an improvement of a recently published experimental methodology based on the Impulse Excitation Technique, which allows nondestructively assessing local elastic properties of composite laminates by isolating a region of interest through a proper clamping system. Different measures of the first resonant frequency are obtained by rotating the clamping system with respect to the material orientation. Here, in order to increase the robustness of the inverse problem, which determines the elastic properties from the measured resonant frequencies, information related to the modal shape is retained by considering the effect of an additional concentrated mass on the first resonant frequency. According to the modal shape and the position of the mass, different values of the first resonant frequency are obtained. Here, two positions of the additional mass, i.e., two values of the resonant frequency in addition to the unloaded frequency value, are considered for each material orientation. A Rayleigh–Ritz formulation based on higher order theory is adopted to compute the first resonant frequency of the clamped plate with concentrated mass. The elastic properties are finally determined through an optimization problem that minimizes the discrepancy on the frequency reference values. The proposed approach is validated on several materials taken from the literature. Finally, advantages and possible limitations are discussed.

IN VIVO DETERMINATION OF ELASTIC PROPERTIES OF THE HUMAN AORTA BASED ON 4D ULTRASOUND DATA

2012 ◽  
Vol 45 ◽  
pp. S19
Author(s):  
A. Wittek ◽  
P. Bihari ◽  
A. Shelke ◽  
T. Nwe ◽  
K. Nelson ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Human Aorta ◽  
4D Ultrasound

Ultrasonic Determination of Liver and Spleen Volumes

1971 ◽  
Vol 27 (2) ◽  
pp. 123-128 ◽  
Author(s):  
T. Kardel ◽  
H. H. Holm ◽  
S. Norby Rasmussen ◽  
T. Mortensen
Keyword(s):  
Ultrasonic Determination
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