Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/3/2009
Publication Date: 4/1/2010
Citation: Liu, C., Latona, N.P., Lee, J. 2010. Acoustic emission studies for leather using dual sensors. Journal of American Leather Chemists Association. 105(4):109-115.
Interpretive Summary: We have been working on developing a nondestructive acoustic emission (AE) testing method to replace the traditional destructive testing methods for leather, thereby reducing the waste in the tanneries. This novel testing method measures ultrasonic sound waves emitted by the leather when it is deformed. In current work, we developed a method using AE signals captured from both the grain and corium sides simultaneously, thereby giving a more accurate assessment of the leather quality. The method can measure the quality of leather without wasting the leather as in traditional destructive testing. Our work provided a quality control/quality assurance method for manufacturing and the potential for being a standard testing method. In short, this research provides the industry with a nondestructive way in which to evaluate the quality of product without damaging the leather.
Technical Abstract: Since leather is sold by the square foot, destructive tests lessen the square footage of the material and infringe on the leather manufacturer’s total profit. Therefore there is a need for developing an instrument to perform nondestructive testing of the physical properties of leather. In this investigation, experiments were designed to pass leather test samples through a pair of rotational acoustic sensors, thereby enabling the collection of AE signals from both the grain and corium and provide a more accurate assessment of the quality of leather. Observations showed a strong correlation between the mechanical properties of leather and the corresponding cumulative acoustic energy. We also used this dynamic method to characterize the grain break of leather. Results showed that the difference in grain break could be determined from the amount of acoustic hits collected from moving the AE sensor over a leather sample. Observations showed the poorer the grain break, the more AE energy was detected. Data also demonstrated that the thicker samples tended to have poorer grain break. In short, this study demonstrated that the tensile strength, stiffness, toughness and grain break could be nondestructively determined by measuring the acoustic quantities with a pair of rotational sensors on both the corium and grain of leather.