Theoretical investigation of turning ability of two-machine sowing aggregate

et al. 2019

In this paper for exploring the mechanisms of formation of traumatic situations, the conditions and circumstances that contribute to them, and the study of the course of events leading to dangers in mechanized processes in agriculture the mathematical apparatus was used developed by the probability theory for Markov random processes with discrete states and continuous time, when the transition of a system from one state to another is possible at any unknown random time. It has been established that the processes of traumatic situations and their consequences can be represented by graph structures, using four states of the "man-machineindustrial environment" system: working and defective conditions of the tractor (machinery), hit of the machine operator into a dangerous and emergency condition (situation). A system of Kolmogorov differential equations was made, in which unknown functions are the probabilities of states of the system as functions of time with the normative condition that the sum of these probabilities will be equal to 1. Introducing the matrix of the intensity of events, the Laplace transform was used to solve the system of differential equations, which allowed the system to be transformed into a linear algebraic system. Elements of the matrix of intensities of the flows of events that bind separate states of the graph were given taking into account the probabilities of accidents with mechanics, established on the basis of the statistics of occupational injuries and data of accumulation of cracks in the array of tractor parts, were determined as a result of defectoscopic control. The results of the research allow in the medium and long term perspective to predict the probable states of the "human-machine-industrial environment" system in the risks of professional injury of agricultural machine operators.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Probability of traumatic situations in mechanized processes in agriculture using mathematical apparatus of Markov chain method

Voinalovych

Hnatiuk

et al. 2019

“…Creation of a database of diagnostic tools should be carried out on the basis of dynamic diagnostic methods [4], which allow to use for diagnostics the parameters of working processes that directly characterize the state of the object; electronic diagnostic tools are developed [5]. This is especially true with simultaneous work in the direction of mutual adaptation of the means and combines to the diagnosis [6]. This requires the appearance of combines equipped with on-board diagnostics based on built-in sensors and electronic equipment [7].…”

Section: Introductionmentioning

confidence: 99%

Research of vibroacoustic diagnostics of fuel system of engines of combine harvesters

Titova

Novitskii

et al. 2019

To determine the diagnostic parameters of the fuel system of engines of grain harvesters, technological and structural parameters of the technical condition were considered. The authors investigate the structural schemes of indicator connection of the purpose (performance) of the fuel system of engines and parameters of the technical state of its structural elements. For example, we consider the modal structure diagram, which characterizes the fuel system of grain harvester engines and parameters of the technical state of their structural elements. For example, we consider the modal structure diagram, which describes the fuel system of the engines. At the highest level there are parameters that describe the process of fuel supply and directly determine the characteristics of injection, or the law of fuel supply. On the lower levels there are parameters that characterize the technical state of the most important elements of the fuel equipment. They are used for elemental diagnostics. Experimental studies of vibration characteristics of nozzles of diesel engines have shown that the energy vibration nozzles manifested most actively at the frequency from 5 kHz to 10 kHz. Application of Hilbert's conversion to vibration analysis has made it possible to use the ability to control the identity of nozzles and identify defects, such as breakage of nozzles and spray gun hangs. When the injection pressure changes from 27.0 MPa to 8.0 MPa, signal duration, which is measured between the front and rear fronts with maximum amplitudes, decreases 2 times. Application of technological cards together with diagnostic means will allow in 1,5 times to cut down the technical equipment due to technical problems at expense of preventing bursts and reducing the fuel consumption by 5-10 %. The range of sensors for diagnostics of diesels, the basic electric circuit of the tool for measuring the angle are developed for fuel supply, the requirements for the computerized system for bench diagnostics of the fuel equipment.

“…The high level of injuries in the agroindustrial complex is due to the fact that most of the technological operations are carried out using morally obsolete and used equipment [1]. However, researchers of occupational injuries in the agroindustrial complex primarily focus on organizational reasons [2] and working conditions [3], largely ignoring the unsatisfactory technical condition of the mobile means of agribusiness production.…”

Section: Introductionmentioning

confidence: 99%

Probability of boundary exhaustion of resources as factor of operational safety for agricultural aggregates

Pisarenko

Voinalovych

et al. 2019

The influence of the presence of fatigue cracks detected in the array of operational defects of typical parts of individual units on the condition of safety of tractors has been analyzed. In the work with the help of a specialized portable vibration current flow defectoscope the presence of cracks in the details of the units of tractors with different operating periods was estimated. The defectoscopic control of more than 500 parts of various applications was carried out in 50 tractors that were in service until 17 years since the date of issue in agricultural enterprises of Ukraine. Defectoscopic inspection was carried out during the defect of the details of these tractors received for repair. Based on statistically valid data, the kinetic dependences of the probability distribution of the accumulation of operational fractures of parts of tractor units in time were constructed. The cracks analyzed in the work were detected using a high-sensitivity pulsed vibration current flaw detector, which allowed us to quantify the size of the cracks that correspond to certain operating lifetime terms. It is established that the process of accumulation of a certain type of cracks has exponential kinetics. The regularities considered in the work reflect the consequences of the statistical process of accumulation of an array of fatigue cracks in the details (knots) of tractors within the limits of the studied range of service life. Exceeding the maximum period of operation of aggregates affects the change in the probability of accidents in mechanized and transport works. It is determined that the deadline for the researched tractor types is 13-14 years.