PSI - Issue 24

Fabio Bruzzone et al. / Procedia Structural Integrity 24 (2019) 167–177 F. Bruzzone et al. / Structural Integrity Procedia 00 (2019) 000–000

174

8

Table 1. Screw features. Mechanical feature

Data

Units

Shank diameter d Head diameter d w

8

mm mm mm

10.4

Pitch Class

1

8.8

Table 2. Sti ff ness results in N / mm. D A d w \ l K d 1

2

4

6

8

10

12

0.96

740045 915950 1372328 1871058 1906086 1912782 1909725

371159 453591 750583 1399276 1492744 1503268 1508126

185841 227476 393186 1000760 1216762 1247923 1268636

123952 151802 266360 776462 1047598 1104153 1154222

92986

74399 91155

62005 75978

1

113909 201398 634309 918058 988064 1058968

1.15 1.92 2.69

161910 536151 817008 893852 977496

135367 464303 736004 816049 907635

3

3.46

Orange surface: stiffness computed by FEM ! ! Purple surface: stiffness computed by VDI 2230

Fig. 4. Comparison between sti ff ness computed with VDI 2230 and the results of the simulations.

the diameter of the bolt head D A / d w and the ratio between thickness of the clamped members and the shank diameter l K / d , as depicted in Table 2. By considering these two ratios as the variables of a space, the surface depicted in Figure 4 can be interpolated by means of a function of two variables. By slicing the graph of Figure 4 firstly maintaining constant D A / d w , assumed as x variable, and then by keeping constant l K / d , assumed as y variable, it is possible to highlight that the so defined curves are power curves with the generic expression:

a = c · x d + e

(15)