MECHANICAL CHAINS: IDENTIFICATION OF DYNAMICAL RESPONSES

Approaches for dynamical responses identification in example of system with three freedom degrees with tie between two of outside elements are offered. First approach bases on using of mathematical models-analogues of automation control theory, second approach bases on rules of transformation of design schemes of chains theory. Conversion from design schemes to equivalent in dynamical attitude of structural schemes of automation control is applied at using of structural method. Feedback tie in automation control system dedicated to the protection object is dynamical responses on external disturbance and at zero value of the disturbance disposed of the coerced elasticity of the system. The using of direct conversion of design schemes for the rules of chains theory shows identical results for both approaches

DEVELOPMENT OF FORMS OF STRUCTURAL MATHEMATICAL MODELING IN DYNAMICS OF MECHANICAL OSCILLATION SYSTEMS: IMPEDANCE AND POSSIBLE VARIANTS OF APPROACH

Offering method of transformation of mathematical models of oscillation systems based on using of structural schemes. Structural analogs of mathematical models used for creature of variants of transfer functions of initial mechanical systems. Technology of transformation of structural schemes with object which has properties of integrated link of second order. Is shown that impedance is local characteristic of frequence dynamical properties of mechanical oscillation systems, in particular, vibration protection systems. Characteristics-analogs of impedance are given. They constructed on base using of movements and accelerations of allocated points. Conditions of ties of relative frequence characteristics are given. Conditions of compatibility of structural models of mechanical chains theory and automation control theory are identified

Волнообразный износ рельсов при торможении

[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].ABSTRACT It was found in the course of the study that oscillations of the vehicle wheelset’s angular velocity during braking should be recognized as the principal cause of rail corrugation. Over a single period, two alternating events occur: an elastic interaction between the wheel and the rail, and their slipping relative to each other causing friction and formation of a valley. The wavelength of corrugation wear increases with the increase of the train speed and the value of the braking torque. In order to reduce the intensity of wear, the track stiffness should be increased, the braking torque reduced, and the suspension’s parameters optimized. Keywords: railway, rail corrugation wear, wheelset, adhesion coefficient, braking torque, track longitudinal stiffness, angular velocity, wheel slip, friction.Текст аннотации на англ. языке и полный текст статьи на англ. языке находится в прилагаемом файле ПДФ (англ. версия следует после русской версии).В процессе исследования определено, что основной причиной волнообразного износа следует признать колебание угловой скорости колёсной пары вагона при её торможении. При этом за один период происходит попеременно два события - упругое взаимодействие колеса и рельса и проскальзывание их относительно друг друга, из-за чего возникает трение и образуется впадина. Длина волны волнообразного износа увеличивается с увеличением скорости движения поезда, величины тормозного момента. Для снижения интенсивности износа рекомендуется увеличивать жёсткость рельсового пути, уменьшать тормозной момент и подбирать оптимальные параметры подвески