A Method of Measuring Relaxation of Stress for Aluminum Alloys

Abstract

A method of measuring stress relaxation by the use of stressing frames, wherein a constant strain is maintained on the specimen, is discussed. The elastic strain introduced into the specimen during loading, at the start of the exposure, and the elastic strain relieved during unloading, at the end of the exposure, are measured. The difference in elastic strains can be used to determine the amount of stress relaxation that has taken place. The method seems to produce reliable measurements and has the advantages that it requires no very costly equipment, and the tests require little or no attention during the exposure periods. Although each test yields only one stress-time data point, many tests can be run simultaneously.