A geometric stress concentration factor, Kt, is used to relate the actual maximum stress to a welldefined nominal stress in a structural member. The maximum stress is given by smax ¼ Ktso, where
smax represents the maximum stress and so represents the nominal stress. The nominal stress is most
often stated at the minimum cross section.
Consider the axial loading shown in Figure 5.9, where the structural member is in axial tension
and experiences a stress concentration as a result of a transverse hole. In this geometry, so ¼ F/A,
where area A ¼ (w d)t. If d ¼ 0.5 w, then Kt ¼ 2.2. Suppose F ¼ 10,000 500 N, w ¼ 1.5
0.02 cm, t ¼ 0.5 0.02 cm, and the uncertainty in the value for d is 3%. Neglecting the uncertainty
in stress concentration factor, determine the uncertainty in the maximum stress experienced by
this part.