Question

The fatigue data for a ductile cast iron are given as follows: (7 pts Stress Amplitude IMPa (ksi 248 (36.0) 236 (34.2) 224 (32.5 213 (30.9) 201 (29.1) 93 (28.0) 193 (28.0 193 (28.0) Cycles to Failure I x 10 3 x 10 1 x 10 I x 107 3 x 107 3 x 10 a) Make an S-N plot (stress amplitude versus logarithm cycles to failure) using these data. b) What is the fatigue limit for this alloy? (c) Determine fatigue lifetimes at stress amplitudes of 230 MPa (33,500 psi) and 175 MPa (25,000psi) d) Estimate fatigue strengths at 2 x 10 and 6 x 10 cycles

Answer 1

Stoers Cycles bo Icalupe tc 948 C36 a) x1oS atg C30-9) 3 X166 13 Cas.o) ,3x10第 to falere plot (s-M plot) s.000o St 6.000o 6.444t 148 a 36 t X10 013 |召X106 ,JO ! 192 193 L9 2 -t-4-tイ! & 0 o00 3 x10

stigu ら6 xtor Cycleう la u less The stsew am prtuck allo a っ and x os Cycles a 1l S.3. around 0240 tPa