DYNAMIC DUROMETER MEASUREMENT OF YOUNG'S MODULUS AND LOSS FACTOR

For laminated plate served in high temperature and high corrosion environment, hard coating can be applied to suppress destructive vibration. While the creation of the dynamic model of hard-coating laminated plate is the premise of the research on vibration reduction. This study was focused on analyzing vibration characteristics of the hard-coating cantilever laminated plate under base excitation. Orthogonal polynomials were used as admissible displacement functions to formulate the displacement field, Lagrange’s equation was used to build the governing equations of both free vibration and forced vibration for the composite plate, and methods of solving the natural characteristics and the harmonic response were presented. A T300/QY89l1 laminated plate with NiCoCrAlY+YSZ hard coating was chosen to demonstrate the proposed method and obtained results were compared with the ones gotten by ANSYS software with the purpose of assessing the rationality of the developed analytical model. Finally, based on the established model, the influences of hard-coating parameters, including thickness, Young’s modulus, and loss factor, on the vibration characteristics of the laminated plate were studied. The results show that increasing the thickness, Young’s modulus and loss factor of hard coating are beneficial to vibration reduction of laminated plate.

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Determination of the Young's Modulus and Loss Factor by Acoustic Bending Vibration Methods

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.297-300.1958 ◽

2005 ◽

Vol 297-300 ◽

pp. 1958-1961 ◽

Cited By ~ 1

Author(s):

Su Hyun Shin ◽

Yong Bong Lee ◽

Sung Soo Jung ◽

Doo Hee Lee

Keyword(s):

Young’S Modulus ◽

Loss Factor ◽

Young's Modulus ◽

Electromagnetic Excitation ◽

Bending Vibration ◽

Metal Disk ◽

Metallic Specimen ◽

Metallic Sample ◽

Good Agreement

A new acoustic bending vibration method of determining the resonance frequency, Young’s modulus and loss factor applicable for both metallic and non-metallic materials is proposed. Measurements were conducted by using both conventional electromagnetic excitation method specified by ASTM E 756 and ISO 6721 and our method for conductive metallic specimen of stainless steel and non-metallic polypropylene specimen. Difference in the mechanical properties observed between both methods is attributed to the presence of a metal disk attached to the non-metallic sample for electromagnetic. However, the good agreement between the results obtained by both methods for the metallic sample ascertains the reliability and advantages of the method.

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Propagation of Ultrasonic Bulk Waves in High Polymers

Rubber Chemistry and Technology ◽

10.5254/1.3546985 ◽

1950 ◽

Vol 23 (1) ◽

pp. 172-184 ◽

Cited By ~ 1

Author(s):

Donald G. Ivey ◽

B. A. Mrowca ◽

Eugene Guth

Keyword(s):

Young’S Modulus ◽

Wave Velocity ◽

Loss Factor ◽

Young's Modulus ◽

Relaxation Times ◽

Effective Modulus ◽

Shear Moduli ◽

Dynamic Young’S Modulus ◽

Bulk Waves ◽

Dynamic Young's Modulus

Abstract The propagation of supersonic waves in bulk rubbers has been studied from 40 kc per second to 10 Mc per second and from −60° to 60° C. The wave velocity was found to increase with decreasing temperature, level off both at high and low temperatures, and increase slightly with frequency. Peaks in attenuation as a function of either temperature of frequency were observed; these occurred at lower temperatures for lower frequencies. The peaks of Butyl, a high-loss rubber, are broader and higher than those of GR-S and Hevea, which are lower-loss rubbers. The results are in qualitative agreement with data obtained by strip methods at audiofrequencies. However, for bulk waves the real and imaginary parts of two elastic constants, the bulk and shear moduli, determine wave velocity and attenuation; hence, independent measurements of shear wave properties are necessary to evaluate these constants. A three constant theory is discussed, assuming a shear viscosity only, so an effective modulus K+4μ/3 is obtained, where K and μ are the bulk and shear moduli. Relaxation times of the order 10™6–10™8 second are indicated. Approximate values of the dynamic Young's modulus are obtained from the effective modulus by assuming that the high frequency dispersion is due to the appearance of a “crystalline” shear elasticity. These results are correlated with low frequency data, and the dynamic Young's modulus and the loss factor are plotted. The loss factor exhibits a maximum in the dispersion region. Results are plotted in the range from 1 to 107 c.p.s., which covers a wider range of frequency than earlier investigations. The necessary distribution of relaxation times is discussed.

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