2121403557

CONOITION OF FERROMAGNETIC MACHINĘ ELEMENTS IN MAGNETIC FIELD - A SURVEY

Abstract

Problems of modem exploitation is first of all ihc activitics supponing the survivability of constructions and devices used many limes for decades. The way of their exploitation. the character and the number of fatiguc cyclcs is unknown. That is why in ncar pcrspcctivc it should rcckon with considerable amount of break-downs of fatigue origin. It is already happcned in power cnginccring and in transport. The procedurcs of non-destructive study of materiał fatigue, that is already exp!oited and h3s unknown history of loads, bccomc an urgcnt ncccssity. Dircct transfer of basie studies formulated in the rangę of energetic and fatigue hypothesis on real object madc from construction Steel, is in principlc impossiblc, although cognitivc value of these researches is undeniablc. The only way is to find the secondary cffcct of materiał fatiguc proccss, likc among others the changes in magnetic parameters and their comparison with starting materiał, that coułd be a fragment of construction, in which the fatiguc changes couldn't happcned from the mechanie point of view.

This purpose bccame the leading one in presented paper. This claboration desenbes the basie parameters and the ranges of magnetic changes in construction steełs. It searches the theoretical connections of materiał structure changes. magnetic parameters changes from fatiguc loads. It proposes the method of magnetic parameters evalualion. It determines their changes in the rangę of elastie and fatigues loads in relation to the basie lcvcl. It joints the methods of simulation researches in mechanics and in magnetism for the magnetic diagnosis purposes. It describcs the scries of researches conductcd in laboratory scalę and latcr in induslry scalę conceming the utilization possibilitics of magnetic changes in ferromagnetie matcnal in the rangę of elastie and fatigue loads. In the rangę of practical realization it is proposed to joint the magnetic parameters changes with number of load cyclcs and give the dcpcndcnccs possible to application. It present the Solutions to industrial application in raiiway transport, and consists in carly dctcction of materiał fatiguc. before appearing the discontinuity. that coułd be detccted by ultrasonic methods.