STRESS-RELAXATION BEHAVIOR OF LEATHER

Leather exhibits a complicated mechanical behavior that can be best ex plained by using concepts of theoretical viscoelasticity. To permit a mathematical description of the time dependent properties of leather u nder different testing conditions, springs and dashpots are used. A si x-element model comprised of three Maxwell units in parallel satisfact orily described stress-relaxation properties of leather. Scanning-elec tron micrographs reveal that fibers remain desegregated upon drying of leather in the presence of fatliquor, while stress-relaxation tests s how that relaxation moduli and relaxation, times decrease with increas e in fatliquor content as well as with increase in temperature and moi sture content. The results obtainable by the stress-relation method sh ould find application in process control, specification acceptance and service evaluation.