Effect of speed of pulling jaws on the tensile strength and stretch of leather

Abstract

The purpose of this investigation was to obtain data on the effect of the speed of the pulling jaws of the testing machine on the tensile strength and stretch of leather. In practice, speeds as low as 0.25 in./min and as high as 12 in. /min have been used in different laboratories. In this study, 1,900 measurements of strength and stretch were made at 6 different jaw speeds, using a horizontal Scott machine of 800-lb capacity. The tensile strength increased with jaw speed, the rate of increase being least between 6 and 12 in. /min. The change in stretch with jaw speed was erratic ; tbe average difference between the stretch at 0.5 in. /min and that at 20 in. /min was 1 p ercent, or no greater than the smallest interval of stretch measured. CONTENTS Page L Introduction __ ______ __ _______ _____ ____ __ ___ __ __ _____ ____________ 207 IL D escription of leathers used _____ ___ _____ _________________ ____ ____ 208 III. Plan of the experiments _______ ___ ___ ___ __________________________ 208 IV. Results-___ ______ ___ _____ ____ _______ _________________ _____ _____ 212 1. Tensile strength of experimentalleather __ ___ ___ __ ________ __ __ 212 2. Stretch of experimelltalleatheL _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 213 3. Light leatheL ___ ____ __________ ___________ _____ _________ __ 214 4. Commercial sole leather ___ _________ __ ____ ____ ____ __ ___