Page 162 - Finite Element Analysis with ANSYS Workbench

8.2 Fatigue and Life Prediction 153

stress cycles. As an example, if we follow the Goodman criterion,
the effective stress  is determined from,
e
 a   m  1

 e  u n
The computed effective stress  is used to further determine the
e
number of cycles N from the S-N curve as shown earlier. Thus,
e
the life of the structural part or machine component can be
predicted. We will employ an academic example and an
application problem to demonstrate life prediction of a structural
part and a machine component in the following sections.

8.2.2 Academic Example
A U-shape plate with its thickness of 0.02 m is shown
in the figure. The plate is made of structural steel material with the
Young’s modulus of 210 N m 11 2 and Poisson’s ratio of 0.3. The

plate is clamped along the left edge while the right edge is
8
subjected to a cyclic pressure loading of 10 Pa. We will use
ANSYS software through the Workbench to estimate the plate life
in form of the pressure cycles.
y E  210 N/m ,   0.3, t  .02 m

11
2
.2 R  .05
 
p  10 Pa
8
.2
x
.2 .6 .2

(a) Starting ANSYS Workbench

 Open the ANSYS Workbench, set the Units menu on the

upper tab to Metric (kg,m,s, C,A,N,V).