PSI - Issue 81

Mykola Stashkiv et al. / Procedia Structural Integrity 81 (2026) 143–150

146

Analysis of the calculation results shows that the following patterns are observed in the sprayer boom elements of this design: the upper and lower chords primarily carry normal forces and bending moments, and the braces perceive torques. The most heavily loaded elements are the upper and lower chords of the primary section of the boom (near the bracket for fastening the boom to the hitch system). A more detailed analysis of the deformation behaviour of the boom allowed us to identify regions with the highest normal stresses in the lower chord at the locations of the braces fastening (Fig. 4).

Fig. 4. Localized deformations of the sprayer boom.

A detailed analysis of the deformation behavior of the sprayer boom lower chord (Fig. 5) allowed to conclude that, from the standpoint of overload-induced plastic deformation, the most critical locations are the transition zones from the curved to the straight segments of the perforation openings (red zones).

Fig. 5. Distribution of the normal elastic strain of the sprayer boom lower chord.

Zones with increased structural stress concentration and plastic deformations due to overloads are highly likely to become initiation sites for fatigue cracks as a result of the development of technological or operational microdefects. 3. Research results and discussion In the case of a crack-like defect in the cross-section of a thin-walled rod-like element, its durability should be assessed using fracture mechanics criteria, such as the stress intensity factor (SIF). To analyze the SIF of the lower chord of a sprayer boom with a crack, a digital model was developed that makes it possible to determine dependence of mode I SIF ( K І ) values on the crack length in the cross-section of a thin-walled bent profile with perforated openings. The general shape of the cross-section of the lower chord of the sprayer boom is shown in Fig. 6.

Fig. 6. Cross section of the sprayer boom lower chord (without crack and with crack).