applied fracture mechanics

192Applied Fracture Mechanicspropagation model, as shown in Figs. 20-22. Therefore, the maximum tangential stresstheory is effective for satisfactorily evaluating fretting fatigue strength in stage I as well as instage II for practical use.Figure 20. Evaluation results on ΔK, K max and K min using minimum stress leading to fracture inexperiments under PC at p=80 MPa when σm= (a)(d) 0 MPa, (b)(e) 400 MPa, (c)(f) -100 MPa for sample A,and σm= (g)(i) 0 MPa, (h)(j) 400 MPa for sample B