No abstract

No abstract

No abstract

The main problem of using roller bearings with direct forming rolling elements in highly loaded units is the edge effect. A significant increase of stresses at the edges of the rolling elements is the cause of the fragility of highly loaded roller bearings, which is a significant problem, especially in such units as rotors of aircraft engines. The solution of this problem in aviation is the use of rolling elements with a modified contact - bombed rollers. This paper presents comparisons of the stress-strain state of contacts of pairs of bodies imitating bombarded rollers of various geometries. The calculation was performed by the finite element method in the ANSYS package. For the calculation, the contact of the roller with a flat plate was used. In the calculation, the stress-strain state of the roller with the direct forming, the roller with the rounding of the face and the bombed rollers with various shapes of the modified forming was evaluated. The calculation model is verified with respect to the classical Hertz formula. The dependence of stresses in the concentration zone on the relative dimensions of the bombarded part of the roller with a standard generator representing an arc of a circle is estimated. A form of the generatrix is proposed, which more effectively reduces stresses in the transition zone of the modified generatrix into the straight line. The proposed form of the generatrix eliminates the main drawback of the classical generatrix of the bombarded rollers - the appearance of a concentration zone in the transition region of the straight part of the roller to the bombed, thus providing a better stress distribution in the roller. The technique used to simulate the contact interaction of rolling elements in a roller bearing can be used to study the stress-strain state of roller bearings of a different geometry, including those used in modern gas turbine engines.

Поступило 24.12.2018 г.Для гетерогенной системы жидкость-жидкость, в которой протекает экзотермическая реакция, исследованы топология и устойчивость стационарных состояний проточного реактора идеального смешения. Показано, что тепловой эффект реакции, величина энергетического барьера и интенсивность массопереноса сильно влияют на тип структуры возникающего стационарного состояния. При этом изменение топологической картины происходит через вырожденные стационарные состояния.Ключевые слова: проточный реактор, стационарное состояние, гетерогенная система жидкость-жидкость, экзотермическая реакция.For a heterogeneous liquid -liquid system in which an exothermal reaction takes place, the topology and stability of the steady states of CSTR are investigated. It is shown that the thermal effect of the reaction, the magnitude of the energy barrier and the intensity of mass transfer strongly influence the type of steady state that arises. In this case, a change in the topological picture occurs through degenerate steady states.