Machinery & Energetics

A representative statistical analysis of the operational information on the reliability of tillage units with oscillatory movement of the working bodies was performed. The results of work under the operating conditions of thirteen cultivators with a total operating time of more than 280 thousand hectares are considered. Operational studies were conducted in 7 regions of Ukraine and characterized various soil and climatic conditions: the mechanical properties of the soil, density, humidity, and so on. The occurrence of sudden failures due to the fracture of the elastic racks of the cultivators' working bodies has been established 42 sudden failures among 260 racks tested were recorded. Using the method of statistical analysis of reliability that meets the industry standard of the Ministry of Agrarian Policy of Ukraine SOU 74.3-37-04604309-904:2011 “Evaluation of reliability indicators with reduced life tests”, the probability of failure-free operation of the elastic cultivator stand and the change of this indicator depending on the operating time of the unit were determined. It is established that the statistical model of reliability corresponds to the theoretical model of quasi-static destruction of sequential systems. The gamma-percentage resource of the rack for sudden failures at various values of gamma is determined. Two possible directions of work have been proposed, which should lead to an improvement in the quality of the elastic struts of cultivators with oscillating motion of the working bodies. The sufficiency of the obtained data is indicated for the application of the concept of the inversion method combining theoretical models of reliability with specific indicators of the statistical model obtained depending on the operating time of the elastic struts to ensure the manageability of the results of improving their quality.

reliability, cultivator, elastic rack, statistical analysis, statistical model of reliability