The fatigue data for a brass alloy are given as follows: Stress Amplitude (MPa)
170
148
130
114
92
80
74
Cycles to Failure
3.7×10 4
1.0×10 5
3.0×10 5
1.0×10 6
1.0×10 7
1.0×10 8
1.0×10 9
(a) Make an S-N plot (stress amplitude versus logarithm of cycles to failure) using these data.
(b) Determine the fatigue strength at 4×1064×10 6 cycles.
(c) Determine the fatigue life for 120 MPa.

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.