A2 cm-diameter, 20-cm-long bar of an acetal polymer (Figure 6–61) is loaded on one end and is expected to survive one million cycles of loading, with equal maximum tensile and compressive stresses, during its lifetime. What is the maximum permissible load that can be applied?
The solution is:
From the figure we find that the fatigue strength must be 22 MPa in order for the polymer to survive one million cycles. Thus, the maximum load is
F =(fatigue strength)d^3/10.18L
F =(22 MPa)(20 mm)^3/ (10.18)(200 mm)
=86.4 N
QUESTION: Where does the 10.18 come from??
(link to figure: d0dfb312a1d442a6b6490f59db1cffca_A.png / http://answers.yahoo.com/question/index?qid=20140108060801AAEQ7mY)
The solution is:
From the figure we find that the fatigue strength must be 22 MPa in order for the polymer to survive one million cycles. Thus, the maximum load is
F =(fatigue strength)d^3/10.18L
F =(22 MPa)(20 mm)^3/ (10.18)(200 mm)
=86.4 N
QUESTION: Where does the 10.18 come from??
(link to figure: d0dfb312a1d442a6b6490f59db1cffca_A.png / http://answers.yahoo.com/question/index?qid=20140108060801AAEQ7mY)
Last edited: