Probability model of cutting effort on the cutters of the executive body with variable cutting parameters
Keywords:
mathematical model, executive body, cutting effort, coal resistance to cuttingAbstract
One of the most important problems in the field of mechanical engineering is to increase
the resource, reliability and durability of machinery, equipment and metal structures while reducing specific quantity of metal. The creation of modern calculation methods for determining technically rational indicators of reliability and durability is central place to solving this problem.
For mountain harvesters, the design and real loads differ, therefore the task of specifying loads in the probabilistic sense for the cutting tool of the machine's executive body is relevant. To determine the load, it is necessary to know the properties of the rock mass as an object of destruction with a cutting tool and the law of formation of loads on the cutters. The destruction of the rock mass by the executive bodies of mining machines is a complex dynamic process of a probabilistic nature; therefore, it is necessary to develop probabilistic methods for determining loads on
the cutting tool. The aim of this work is to develop a probabilistic model of cutting effort, which allows a more adequate assessment of the actual load on the cutting tool and the elements of the executive body. In the article, the cutting force model is presented in the form of additive components. To build probabilistic models, the laws of spatial-temporal variability are used – the resistance of coal to cutting, which appear when the combine is moved, and the cyclic nature of
the destruction process, which appear when the tool moves. The probabilistic model of the first component is an elementary random process. The probabilistic model of the second component is a high-frequency narrowband random process, the analytical representation of which is carried out using non-canonical spectral decomposition of random processes. Refinement of the basic probability characteristics of the resistance of coal to cutting according to the law of probability distribution is achieved by using higher moments of distribution. The developed probabilistic model of the cutting effort makes it possible to introduce the time factor into the strength calculations as a condition necessary for calculations for fatigue life.
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