(i) In no more than 50 words, explain what is fatigue failure. (ii) Explain the terms endurance limit and fatigue strength in the context of failure mechanics. Illustrate your answers with diagram(s). (b) A low-carbon steel has a reversed stress fatigue limit of 230 MPa, a UTS of 860 MPa and a yield stress of 380 MPa. (i) Estimate the safe range of stress for a repeated cycle based upon the Gerber and Goodman predictions. (ii) Estimate the safe range of stress for an alternating tensile cycle with mean stress of 185 MPa and the peak stresses based upon the Soderberg predic- tion. Gerber: = 0 " 1 M UTS 2# Goodman: = 0 1 M UTS Soderberg: = 0 1 M Y