Nondestructive evaluation of leather based on acoustic emission

The physical testing of leather is currently a destructive process, wherein cutouts are taken off the tannery floor for mechanical testing. These destructive tests are not only time-consuming, but also wasteful of leather. Therefore there is great incentive to develop a nondestructive test that will drastically improve leather quality control. We recently examined the feasibility of using the acoustic emission (AE) technique to nondestructively measure the mechanical properties of leather, particularly tear strength and softness; both properties are critical for leather especially for upholstery and automobile applications. In this investigation, a rotational acoustic sensor was contacted with the leather samples to collect their AE quantities and properties. Observations showed an excellent correlation between the tear strength of leather and the corresponding acoustic counts, read from an acoustic emission analyzer. Data also indicated a close relationship between the softness of leather and the corresponding ratio of acoustic hits to energy. The observed phenomena implied that the tear strength and softness of leather can be nondestructively determined by measuring the acoustic quantities with a rotational sensor crossing over the leather to be tested. The results of this research have become the framework in designing an in-line nondestructive evaluation method for leather quality.