Measurement of ductile material damage

The damage related to the voids present in ductile materials is an importan t parameter in some failure criteria. It is possible to express this damage in terms of changes in the elastic modulus, hardness, and electrical poten tial. This article reports on some damage measurements in a mild steel spec imen subjected to traction using different experimental techniques. The res ults indicate different values for the damage on the same specimen, accordi ng to the technique employed, suggesting that the damage parameter used in a theoretical model must be carefully related to the appropriate constituti ve law.