Page 208 - Biaxial Multiaxial Fatigue and Fracture

192 I: LAGODA ET AL.

1 Determination of the stress tensor oij(t), (ij = x, y, z)

2 Calculation of the strain tensor Ejj(t), (ij = x, y, z)

1
I 3 1 Determination of the normal strain and stress E,,(t) and o,,(t)

4 Calculation of the equivalent energy history W,,(t)

I
I 6 1 Counting the cycle and half-cycle amplitudes in the critical plane

7 Fatigue damage accumulation

I 8 1 Fatigue life determination

Fig.4. Algorithm for the fatigue life determination with use of energy parameter
Since in our experiment shear stress and shear strain coming from torsion with the gradients
of these quantities, we introduce the correction coefficients kzCF, Eq. (20) and k,"'", Eq. (21)
into Eqs (27) and (28). Then we obtain the following equations

E,,(t) = itfE,,(t)+ m~Eyy(t)+i?~~,(t)+2k~CF&m,,Exy(t) (30)