The load history shown in the Fig. 1 is repeatedly applied to

The load history shown in the Fig. 1 is repeatedly applied to a cantilever (beam, no rotation) made of hot rolled 4340
(HB 243) steel. The geometry, dimensions and the location of the loading force F are shown in Fig. 2. Use stress-life
method to solve how many times can this history be applied before failure. Explain all steps and assumptions.
Submission deadline is 3.11.2014 at 14:00.
𝐹
𝑟 = 6 𝑚𝑚
3
1
5
3
7
𝑟 = 3 𝑚𝑚
9
1.5
11 13 15
𝐹 [kN]
50
-3.0
-4.5
46 48
10 12 14
2
4
6
8
Fig. 1 Loading history
∅ = 100 𝑚𝑚
∅ = 60 𝑚𝑚
∅ = 30 𝑚𝑚
45 47 49
60 𝑚𝑚
100 𝑚𝑚
Fig. 2 Geometry