Experimental Determination of the Specific Strain Energy of 65G Steel Under Cyclic Loading

We develop an experimental procedure for the construction of cyclic stress-strain diagrams of the material in front of the tip of a fatigue crack by using the method of digital image correlation and an algorithm for the calculation of the specific strain energy of the material subjected to cyclic loading. We compute the strain energy for three values of the fatigue crack-growth rate corresponding to the Paris section of the kinetic diagram of fatigue fracture. It is shown that the total energy spent for the damage to the material under cyclic loading is comparable with the critical value of the specific strain energy under quasistatic loading.