Abstract

Four bovine leathers subjected to five stretching procedures in water at temperatures between 60 and 80°C with drawing ratios between 1.20 and 1.40 were analyzed to demonstrate the suitability of Nutting’s model to fit the stress-relaxation of samples strained at 20%. The influence of the specimen direction and the mechanical conditioning (subjected to two cycles of straining at different pre-loading level from 0.5 to 10daN) were considered. Nutting’s model gives estimators of the initial stress and the relaxation rate. The initial stress is influenced by stretching treatments, specimen direction and mechanical conditioning. The influence of the stretching treatments on the relaxation rate depends on the stretching ratio, temperature and type of leather.