SIMULATION OF ACCELERATED TESTING OF KNIVES OF CUTTING-REDUCING DEVICES OF FORAGE HARVESTERS
A method is proposed and a technique is developed for accelerated bench tests in laboratory conditions of knives of cutting-reducing devices of forage harvesters. One of the main purposes of the developed method is an experimental comparative assessment of the long-term performance (according to the wear resistance criterion) of various knife options (according to the materials for their manufacture and structural and geometric parameters). The proposed test method solves the problem of assessing the wear resistance of agricultural harvester knives by two parameters: physical depreciation and dulling of their cutting edge. A flexible belt with an abrasive fixed on one of its surfaces is used as counter-specimens during testing, which allows for wear with sliding impact and thereby significantly accelerates the process of knives damage. The technique makes it possible to test simultaneously two knives made using different technologies, under comparable conditions. In addition, to speed up testing, not one, but several counter-specimens are mounted on the test equipment. As a result of such tests, the process of impact-fatigue loading with slipping is simulated and the damage to the knife is reproduced, which is close to the operational one: wear and an increase in the cutting edge radius. Using the developed technique, comparative accelerated tests of imported steel and domestic cast iron (produced by OJSC “Gomselmash”) knives made using various technologies were carried out. The tests conducted made it possible to quantify the difference in the service characteristics of the cutting drum knives made using various technologies, which confirms its usefulness and efficiency. The developed technique was approved in accordance with the established procedure and is used for bench testing of knives at OJSC “Gomselmash”.