Question

The S-N curve of a material is described by: log N = 10(1 - Olomax) A component made from this material is subjected to 105 cycles at oa = 0.40max. Next, it subjected to 103 cycles at oa = 0.60max If the cyclic load is increased once more to 0.80max, how many more cycles will the material withstand?

Answer 1

Log N= 10/12 10(l- enor) When Ga= 0.4&man ni=105 Cycles . So, Ni=? LogNo= 10/1- 014 saman sman Log Ni = 10x0.6 Logni Ni = 106 When Iman Sa=0.66man N2= 103 Cycles Log N2 = 10 x 10x11 0.6 sman Log N2=4 104 When Ga=0.85man Log N3 = 10x (1- 0.86man Sman Log Ny 2 N3 = 102 )

By Miner's Rule ni Nz Ni cabretsen N3 N3 + = 1 Ni N3 1 105 106 103 104 t 102 + ol- Nz 100 Sin10 N3 100 0.1-0.1 -0.8 so Eyeler Mz= 80 80 more Cycles will the material withstand. Hp i ti tist 13