Influence of the Working Media and Maneuvering Loading Mode on the Service Life of Spraying Booms of Field Sprinklers
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INFLUENCE OF THE WORKING MEDIA AND MANEUVERING LOADING MODE ON THE SERVICE LIFE OF SPRAYING BOOMS OF FIELD SPRINKLERS О. E. Andreikiv,1,2 А. V. Babii,3 and І. Ya. Dolinska4
UDC: 539.375
We propose a method for the determination of the residual service life of wide-coverage spraying booms of field sprinklers with regard for the maneuvering mode of their loading and the action of corrosive media. This method is based on the energy approach developed earlier, the computational models of propagation of corrosion cracks under static and cyclic loads, and the scheme of the maneuvering loading mode. In the realization of the proposed model, we use a boom made of St.3 steel. Keywords: wide-coverage booms of field sprinklers, corrosive media, maneuvering loading mode, residual service life, kinetic diagrams of growth of corrosion and corrosion-fatigue cracks, stress intensity factor, period of subcritical growth of corrosion-fatigue cracks.
Introduction Metal structures of agricultural machines often fail under the influence of atmosphere, soil, and pesticides even in the absence of force loading [1–4]. Thus, in particular, the machines used for the protection of plants and application of liquid fertilizers suffer the action of liquid and atmospheric corrosion. Its effect is especially pronounced for their metallic parts susceptible to corrosion whose rate increases both as a result of contact with soil, vegetation, pesticides, and fertilizers and in the case where the paint coatings are damaged. This is the cause of failures of up to 33% agricultural machines. The strength of carbon steels and gray cast iron decreases by 40–55%, and the degree of wear of joined components becomes 2–4 times higher. Every year, domestic agriculture suffers enormous material losses caused by the violations of the rules of storage and the requirements of corrosion protection. To predict failures, it is necessary to develop new methods aimed at the evaluation of the residual service life of agricultural machines with regard for the action of operating loads and corrosive media. At present, the methods aimed at the evaluation of the residual service life of the elements of these machines in irregular maneuvering loading modes and under the action of corrosive substances are not well developed. This is why, in the present paper, we formulate a computational model for the evaluation of the residual service life of the spraying booms of field sprinklers operating in the maneuvering loading mode and under the influence of corrosive media. 1 2 3 4
I. Franko Lviv National University, Lviv, Ukraine.
Corresponding author; e-mail: [email protected].
I. Pulyui Тernopil National Technical University, Ternopil, Ukraine.
Karpenko Physicomechanical Institute, Ukrainian National Academy of Sciences, Lviv, Ukraine.
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 56, No. 2, pp. 26–32, March–April, 2020. Original article submitted September 24, 2019. 166
1068-820X/20/5602–0166
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Springer Science+Business Media, LLC
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