FATIGUE ANALYSIS : PROBLEM 6.9 SOLUTIONMUHAMMAD JOSHUA YB1406563866DEPARTMENT OF METALLURGY AND MATERIALS

APPLICATION OF BASQUIN’S LAW

= constant• ≈ cycles

0.07 < b < 0.13

QUESTION

Cyclic fatigue of an aluminum alloy showed it failed under a stress range σ = 280 MPa after 105 cycles, and for a range 200 MPa after 107 cycles. Using Basquin’s law, estimate the life of

the component subjected to a stress range of 150 MPa.

SOLUTION 1

• 1 = 280 • 2 = 200• 1 = • 2 =

= (

=

= (

= b

= 0.073

• = 150 Mpa ; Nf ?

= = 5 X 10^8 Cycles

= constant = 648.775

SOLUTION 2

•

• Jika A dan b diketahui

∆𝜎 (𝑁𝑓 )𝑏

• Sf = 200 ; Nf = 10^7• A = Sf / • = 200 / 10^(7 x -0.117)• = 1318.3

• Sf = 150 MPa; Nf = ?

• = 1.2 x 10^8

• Note : Result difference due to the differences of laboratory condition fatigue limit and nature condition fatigue limit

REFERENCES

• Meyers, Marc . 1998. Mechanical Behavior Of Materials , Second Edition . Cambringer.• ocw.mit.edu, lecture’s Notes• Institute technology Of India, lecture’s Notes (Ocean

Structures Engineering)• Smallman , R.E. 1998 . PHYSICAL METALLURGY And

ADVANCED MATERIAL ENGINEERING. Prentice Hall.