PSI - Issue 48

Đorđe Đurđević et al. / Procedia Structural Integrity 48 (2023) 88 –95 Đurđević et al / Structural Integrity Procedia 00 (2019) 000 – 000

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Similar problems with stress concentrations are discussed by Antoni and Gaisne (2011), Shi et al. (2002) and Shun et al. (2022). Experimental results (Aramis) and the results obtained by numerical methods from above mentioned fields were reported by Bajić et al. (2017) and by Đurđević et al. (2021). All designed and constructed struc tures inevitably have a change in geometry that causes stress concentration. Current standard methods of calculations and testing cannot accurately determine and anticipate the intensity of geometrical discontinuity effect on the structure deformation and stress. The excavator breakdown from surface mine, Fig.1, prompted us to examine connecting lugs numerically and to confirm numerically obtained results with the experimentally. The lug that led to breakdown of excavator is shown in Fig.2. The accident occurred due to the failure of connecting elements.

Fig.1. Breakdown of rotary excavator

Fig.2. The lug that led to the breakdown of excavator

2. Analysis of connecting lugs Geometric shapes of structural elements for connection used in the numerical analysis of this paper are shown in Fig.3. and Fig.4. All analys ed connecting lugs’ structural elements are made of structural steel S355JR. The first and second numerical analysis included connecting lugs with dimensions as shown in Table 1. and axial distance between holes of the analysed connecting lugs U is 86 mm. Dimensions and shapes of the lugs used in the third part of numerical analysis are given in Fig. 4.

R

B

d

t

Fig. 3. Geometric shape of analyzed connecting lug

Table 1. Dimensions of connecting lugs according to Fig.1.

2 R d

Designation of connecting lug

d ( mm ) R ( mm ) B ( mm )

t ( mm )

U

12

18

18

10

3