Kukhtov V. Methods of estimation of durability of disigns of the chassis of wheel tractors

Object of research: processes of the damage accumulation of constructive elements, assembly units and wheeled tractor chassis units. Research purpose: development and updating of existing methods, theoretical and experimental substantiation of the methods of evaluation, rating, service life that are applied in the process of the design of wheeled tractor chassis and allow to reduce volume and time period of experimental and finishing work. Research methods: a set of the numerical methods of elasticity theory, probability theory, random function theory, theory of reliability and the finite-elements method as well as the methods of the experimental research of loading and a technical state of constructions during operation, tests and maintenance. Equipment: Pentium - 3,6 MHz, 512 Mb OZU, Windows 2000, Office 2000. Theoretical and practical results: the method of the life service evaluation of details that lose their service ability because of fatigue damage is developed and scientifically substantiated and the method simultaneously takes into account geometric features, material strength characteristics, operation conditions and the spread of a failure rate; regulations of the change of wheeled tractor chassis detail life period that use operation ability due to fatigue damage in relation to material strength characteristics, geometry change and loading modes are established; data about the damages of the typical details in chassis units in the new models of type 30 kH tractors and operation modes of the loading of chassis constructive units during agricultural and transportation works are put into practice; characteristics of the operation modes to load a steering hydraulic actuator in the constructive elements of a frontlift articulated frame are investigated and schematized; the developed methods, algorithms and calculation programmers can create a new basis to both evaluate and rate life service that is essential in terms of practical use as it enables to evaluate the correspondence of life service calculated characteristics to norms established. It enables to make corresponding corrections when choosing materials, covers, geometry, operation modes of loading etc. Implementation: The results of research are put into practice when designing and testing equipment in Ukrainian enterprises, namely, the KhTZ open joint stock company (Kharkiv), the Sudmash state plant, (Kherson), the UkrNIIPIT (УкпНИИРИТ) (Kiev region), the Southern Ukrainian state machine-testing station (Kherson).