olgtltligtthis fatigue lab test in material science .can you send it as excel file pleaseSubmission Date: Next Lab

Experiment: Fatigue Test

Problem 1

The fatigue data for a brass alloy are given as follows (each question carry 1 marks):

Stress amp,

S(MPa)

170

148

130

114

97

80

74

Cycle to

failure (N]

3.7×104

1.0×105

3.0×105

1.0×105

1.0×10′

1.0×105

1.0x10quot;

a) Make an S-N plot of the data.

b) Plot in 5 vs /n N and report your observations. Determine the material constants A and B by

fitting this plot to the equation S- AN .

c) Determine the fatigue life for 120 MPa.

d) Determine the Endurance limit or Fatigue strength whichever is applicable for this metal.

Problem 2

The fatigue data for a steel alloy are given as follows.

Stress amp,

S(MPa)

470

440

390

350

300

290

290

290

Cycle to

failure (N)

1.0×10*

3.0×10

1.0×105

3.0×10

1.0×105

3.0×106

1.0×10

1.0×108

e) Make an S-N plot of the data.

f) Plot In 5 vs In N and report your observations. Determine the material constants A and B by

fitting this plot to the equation S=ANquot;. Is A and B the same as in problem 1? Why or why

not?

g) Determine the Endurance limit or Fatigue strength whichever is applicable for this metal.

h) Estimate fatigue strength at 2.0x 10* and 6.0x10quot; cycles.

If you run a component made of this steel alloy at stress amplitude of 470 MPa and such

that you stop using it at 1.0 x 10′ cycles, determines the factor of safety on life.

j) If you run a component made of this steel alloy for 1.0 x 10# cycles but at 250 MPa, what is

the safety factor on stress?Mechanical Engineering