Матеріали до кандидатського іспиту з англійської мови на тему: «Підвищення надійності та поліпшення показників роботи будівельних машин, які використовуються в умовах динамічного перевантаження»

Міністерство освіти і науки, молоді та спорту України

Харківська національна академія міського господарства

Кафедра іноземних мов

Матеріали

до кандидатського іспиту з англійської мови на тему:

«Підвищення надійності та поліпшення показників роботи будівельних машин, які використовуються в умовах динамічного перевантаження»

за фахом: 05.23.01 – «Будівельні конструкції, будівлі та споруди»

Харків – 2012

THE PROJECT STATEMENT

The title of the thesis is increasing reliability and improvement of working parameters of new machines aimed at use in conditions of intensive dynamic overloading.

The subject of the thesis is dynamics and strength of machines.

The subject of the research work is synergetic effect in the problems of spatial structure objects vibration tests.

Strength and constancy functioning tests and forecasting are considered to be a central point in a complex of measures on increasing reliability and improvement of working parameters of new machines aimed at use in conditions of intensive dynamic overloading. Dynamic loads (vibrations, blows, and their complex influence) are known to accompany the work of means of transport, ships, aircraft, industrial structures and buildings, as well as other objects with revolving and moving nodes and machines. Their work causes strength decrease of objects which can be put out of operation. That is why tests of objects under conditions of multicoordinate vibration influence are of great importance for the majority of devices, machines, apparatus, structures and buildings, produced at different industries enterprises. It’s practical application provides quality increase of particularly nonlinear vibration rejections of multivariate parametric vibration objects research and validity of results. It also provides time and costs saving.

The majority of electric hydraulic mechanical units (EHMU) of machine building, aircraft and space technology are a great number of nodes and blocks, installed on a bearing structure (body). They refer to spatial structure objects class, mechanical scheme of which is a spatial system of inertia, springy and diffusing elements.

To achieve stand testing conditions corresponding to the most dangerous mode of the test, it’s necessary to consider dependences and relations between vibratory motion parameters of working elements EHMU and its body under conditions of synergetic effect influence, i.e. the effect increasing interaction of spatial vibration components of the stand platform.

The Background of the Problem

The term „Synergetic effect of the first type” has been defined in tasks of vibratory reliability tests as an effect of increasing action of multicoordinate vibration parameters of spatial stand platform (a body of the machine) on the absolute vibration parameters of the EHMU body. For nodes installed on the body of EHMU, the effect of mutually increasing action of forward angular vibration of the EHMU body (or the platform of the spatial vibrostand) on relative vibration parameters of the EHMU nodes has been defined as “Synergetic effect of the second type” [1].

One-coordinate stands of horizontal, vertical and inclined vibration methods have been best worked out at present [2]. Essential contribution to the development of these methods has been made by such researchers as Bozhko E., Bolshih A.S., Genkin M.D., Gnoevoj A.V. and others.

The most famous methods, worked out by M.D. Genkin and Y.I. Yorish [3] are expected to provide the necessity of the object reinstallation on the table of vibrostand simultaneously with its order orientation change. The total time of the stand vibration influence under conditions of one-coordinate excitation is equally distributed among directions. Actually, as it’s shown in their work, first, duration of the vibration loads influence on the test object will be doubled, resulting in the object vibroreliability failure. Second, the accuracy of the operating vibration condition of the tested object representation and reliability of object vibration tests are +known to decrease.

The difference between two-coordinate vibration loading and one- coordinate vibrostand tests has been described in the works of such scientists as Bozhko A.E. and Genkin M.D. However, a fundamental problem of vibration tests has not been considered in these works. The investigation (analysis and studies) of dependencies of forced and resonance oscillation amplitudes of the object from parameters of the outside multicoordinate kinetic influence imposed to it are to be researched. That is why while testing the indices of the vibration activity factors of a diagnosed object are rather low and may cause maintenance failure.

It is stressed in the works of Bozhko that more than 55% of aircraft equipment failures are conditioned by the fact that incomplete factors of outside influence are not taking into consideration, that is synergetic effect of influence component parameters has been ignored. It has been determined that the purpose of the equipment tests is: