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Study On Tribological Behaviors Of Materials And Related Applications Under Magnetic Field Or With Water-lubricated

Posted on:2017-02-16Degree:MasterType:Thesis
Country:ChinaCandidate:L Z LiFull Text:PDF
GTID:2272330509952394Subject:Precision instruments and machinery
Abstract/Summary:PDF Full Text Request
The tribological behaviors and wear stateof mechanical equipment will directly affect the performance of system. In order to ensure the normal operation, the system needs to be adjustedaccording to the of tribological behavior under different environment.Under magnetic field, oxidation ofmetal materials will be accelerated, magnetostriction will happen, surface microhardness and plasitcity of metal materials will be increased, internal stress will drop. These physical property changes will have influence on the tribological behaviors.Study of tribological behaviors under magnetic field not only help machine work efficiently, but also help the precision instrument work properly. Furthermore, more and more green ships equipped with water-lubricated polymer stern tube bearings are manufatured for the concept of enviroment-friendly vessels and simplification of bearings. It is important for optimizing the design of the ship power system, improving the operation efficiency and solving the problem about violent vibration during starting process.In this study, the tribological behavior of reciprocating motion between ferromagnetic films coated with polymethylmethacrylate films under a magnetic field is evaluatedon an UMT-3 tribo-tester. The tribologicalproperties of water-lubricated polymer bearing materials of ultra high molecular weight polyethylene(UHMWPE),Thordon and Feroform pins with ZCu Sn10Zn2 plates are investigated with water-lubricated on an UMT-3 tribo-tester. As an extension of application about magnetic tribology, this study also include Frequency-broadening Processing of Magnetorheological Elastomer Vibration Absorber and Optimization of Simulink Simulation. Specific work is as follows:First,The system of ferromagnetic films coated with PMMA films based on glass called ferromagnetic/PMMA doublemembrane in this paper is prepared for avoiding the oxidation of ferromagnetic materials. The tribologicalbehavior of reciprocating motion between ferromagnetic films coated with PMMA films under a magnetic field is evaluated.The influences of magnetic force and the changes of the physical properties of the friction pair on friction andfriction coefficient, which are both induced by the magnetic field, are analyzed. The theoretical analysis results are ingood agreement with the experimental date. This work provides a basis for designing and controlling magnetic filminterface media.Second, ultra high molecular weight polyethylene(UHMWPE), Thordon and Feroform pins with ZCu Sn10Zn2 platesare prepared for test. Coefficient of friction(COF), friction forces and stick-slip phenomenahad beensystematically characterized and compared with their surface energy, self-lubricating properties and wear mechanisms. Results showed that the starting processcaused the significant and different stick-slip phenomena of the polymers, and friction force presented displayed the triangle-typalcycle fluctuation with therelative velocity. Theseresults are helpful for design and materials chosen ofwater-lubricated polymer bearing.Last,as the extension application of magnetic tribolgoy, the stduy design and optimize the mathmatical model of double-degree MRE vibration absorber including damping. The model which is described in the paper implement the MRE vibration absorber by changing the magnetic field intensity. The study structure the time-domain model and frequency-domain model based on Matlab Simulink. The simulation analysis the principle and the frequency-broadening processing of vibration absorber which provides the design basis for the application of magnetorheological elastomers in semi-active vibration absorber.
Keywords/Search Tags:Tribology, Ferromagnetic/Polymethylmethacrylate double membrane, Water-lubricated stern tube bearings, Magnetorheological Elastomer Vibration Absorber
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