2.4. Strength computation under impact
A weight Q falls from a height h onto a steel I-beam shown in fig. 9. determine the beam maximum deflection and maximum stresses developed at its cross-section at the point of impact. Analysing the influence of the beam weight and the way the stress changes if one of the supports is substituted with a damper in the form of a spring (if spring compliance is ). The steel elasticity modulus is E = 2·105 MPa, allowable stress under impact d = 140 MPa.
Take the necessary data for computation from Tables 14, Tables 15 and Tables 16.
Scheme I Scheme II
Fig. 9
Table 14
Variant /group No./ |
201 |
202 |
203 |
204 |
205 |
206 |
207 |
208 |
209 |
210 |
211 |
212 |
I-beam |
27 |
30 |
24 |
22 |
20 |
18 |
16 |
14 |
33 |
36 |
|
|
h, cm |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
4 |
5 |
6 |
|
|
Q, kN |
1,4 |
1,3 |
1,2 |
1,6 |
1,5 |
1,0 |
0,9 |
0,8 |
0,7 |
0,6 |
|
|
Table 15
Operation factors |
Variant number, Scheme I |
|||||||||||||
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
|
a, m |
2,4 |
2 |
1 |
2,3 |
3 |
1,1 |
1,8 |
1 |
1,6 |
2,8 |
2,2 |
1,5 |
0,8 |
2,7 |
l, m |
5 |
4,5 |
4 |
4,8 |
6 |
4,2 |
3,8 |
4 |
5 |
6 |
5,5 |
4 |
3 |
5,4 |
, cm/kN |
2 |
3,4 |
2,1 |
2,5 |
2,2 |
2,8 |
3,0 |
2,0 |
2,4 |
3,4 |
3,2 |
2,7 |
2,5 |
2,8 |
Operation factors |
Variant number, Scheme II |
|||||||||||||
15 |
16 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
24 |
25 |
26 |
27 |
28 |
|
a, m |
1,2 |
1,4 |
1,5 |
2 |
2,2 |
2,4 |
2,6 |
2,8 |
1,7 |
2,5 |
1,7 |
1,8 |
2 |
3 |
l, m |
4 |
5 |
3,8 |
5,5 |
6 |
5 |
6 |
5,8 |
4,4 |
5,6 |
4 |
4,2 |
4,5 |
6,8 |
, cm/kN |
2,2 |
3 |
2,4 |
2 |
3,2 |
2,5 |
2,8 |
3,1 |
2,1 |
2,7 |
2,3 |
2,2 |
2,8 |
3 |