Characterization of damage and toughness of 5052 aluminum alloy based on continuum damage mechanics

Elastic modulus was applied to estimate the damage variable based on continuum damage mechanics. A damage evolution equation was derived and the variation of damage characteristics with deformation was also discussed. Repeated loading-unloading tensile tests were conducted on 5052 aluminium alloy. It was found that the yield strength increased with the plastic stain until fracture, then the yield hardening model was established. An equivalent sine model was employed to illustrate stress-strain relationship according to the principle of double atoms model. Toughness indicator and plastic deformation energy indicator were introduced to describe the toughness feature in metals and the parameters were formulated by conventional mechanical properties of metals. It was shown that the parameters can well characterize the material toughness in deformation process and plastic energy in crack propagation.