Acoustic properties of nitrile butadiene rubber (NBR) specimens with carbon black as filler were investigated with different sulfur contents in the frequency range of 300-1000 kHz. Their mechanical properties, such as density, hardness, tensile strength, were conventionally measured and correlated with their acoustic properties. Sound speeds in the specimens were increased with an increase in the sulfur content. The variation of sound speed was about 2-5% in the specimens, whereas the variation of density was less than 0.4%. Enhanced acoustic transmission was also observed with increasing sulfur content. It may be due to the hardness change from the increase of crosslinking density in the specimens. These results show that the mechanical properties of NBR can be nondestructively and accurately determined with the acoustic property measurements. By use of the desired mechanical and acoustic properties, the utilization of the NBR for underwater applications becomes less difficult.
Acoustic and mechanical properties of nitrile butadiene rubbers (NBR) with the variation of the carbon black contents were investigated. All the composition contents except carbon black were kept constant in the specimens. Acoustic measurements were performed in the frequency range of 300 -800 kHz. Increase of the carbon black contents in the rubber resulted in an increase of the mechanical properties such as density, hardness, tensile strength, and glass transition temperature. The sound speed and attenuation in the specimen were mainly affected by the carbon black. The sound speed increased with the carbon black content and depended on the square root of the ratio of hardness to density. However, the sound attenuation was not affected by the carbon black content variation but by the existence of the carbon black. The results with carbon black content variation were also compared with those of the sulfur content variation having a fixed carbon black content (K. I. Jung et al., J Appl Polym Sci 85, 2764 -2771, 2002. These results show that the variation of acoustic properties can be used to nondestructively evaluate mechanical properties and to estimate the carbon black content variation in NBR.
Feasibility of nonlinear acoustic modulation technique [K. I. Jung and S. W. Yoon, Proceedings of Internoise 2000, Nice, France, p. 205 (2000)] was discussed for nondestructive defect evaluation. Such nonlinear acoustic technique can be applied to localize a defect in a solid rod and also extended to layer-structured media. In this study, nonlinear acoustic technique with ultrasonic guided waves is introduced. Nonlinear acoustic responses from a defect are observed with guided waves in a 2-D structure. The defect was oriented in the direction of guided wave propagation. The experimental results show that the nonlinear acoustic technique with ultrasonic guided waves seems feasible for nondestructive evaluation of 2-D structure. [Work supported by BK21 Program in Korea and by the Basic Research Program of KOSEF (R01-2000-000-00014-0).]
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.