Dynamic Stability of Linear Misaligned Journal Bearings Via Lyapunov's Direct Method©

Abstract

Patras 265 00, GreeceOne rf //re ntosl iinportnnl problenrs oJ lato~l)e (~ri,cg .$yste?~~s, 1/21? slnhilily /),o/)lern, ~?.s/~~?cirrlly in tire case lhnt L/LI? lalor is i n ?nisnlig?ze(l posiliorr irc r~!.s/~ec/ ioillr the I)etir-ing, is examined i n 1l~i.s pnper. 1. y np~t no71 :s rlircc~ rnc~ltocl rurrs flrcJiirre(1 i n lhis nnnlysis inslead o/ n cI(~.s.sic(rl eig~!nr~(tl~ce (tn(~lysis in ordm lo ohlnin the stcrbilil~ conditions in //re fir111 c!f rrrtrrlylicrtl ex/)re.s.sio,r.s. '1'111: eig/~/ (lynronic coeJJci:ren/s (bur s/@;/file.s.s n,?d fiur dnmnj~ing) j ) r tl~e (i~ligtred jorr rnnl 1)1?(1ring or /he 32 clynn?nic cocJiJcienl.s ( 1 6 ,stiSS,~e.s.s cr,nrl 16 (10 rnping) /or lire rn~i.snli&vzI?d case ccm be ~rsecr! here in order lo o1)lnin [/re rri;/filcrlytic(~l slnl~ility conditio11~~ (ind 1/26 stability cl~co./s. 7Xe r(!.s!strl/s r!pll~e pre.wn/ ini~mtig(~tion ( L~I ? con~i)nlarl ruith tI~e r(!,s~tlls cotfl cs/~o.i~narrt.s irz //re liler(ilrtre nnd c~reSr,?tntl lo /)e i n good c/g,aotloll. ? . I /re rigid ,nlor ,tnor/el runs cllosor ji)r ruork in order lo cor~cen1,nle on t l~ tni.sctlig~re(l 61?an'ng hehnvio,; lhrts nvoirling 111e JIe.~ihle sIl(f1 i~dl~rtenc~! on 1/11! sy.sle~n. ~' / L C tnodcl zcsed is comprzse(L o/rr rigid roto?. n1oro11ecl 011. tioo line(~r iso/roj)il)i~ nii~~~ligncd benritrgs (r~nrl is used lo d(mclo/) clo.scrl-Ji,,rn stnbilily o-ile,z'n. Usi~rg tlrc 111(!1hod pre.so~le(l in 1lri.s pnj~n; Ihe rrnnlylicril exi)rI?.ssiorrs j ) r 111s slnbility o/ rni.snli&o?ed jo~orrnl he(r rings re ohmined 171. Final manuscript approved December 11, 1995 1he close(1 j o n r r o/ inequnlity coi~slminls. The inJluence o/ lhe 7nisc~-lipmen1 nngles on the stnbilily o/ 1/1e s)is/e~n is (lernonstmfed rs n Ji~ndion o/ 1/11? slendaness rt~lio nnd 1/ze diinensionless muss. Finnlly, /he comnj~arison oJthe st(lbi1ily rc~~zgcs, .usingjrsl the eigI11 cr11d t/~eir the 32 dynamic cocJiJcienls, gives l l~e degree o/i~nporlrince orall 1/11?se /mn.s, and from total point o/vieru o/the proj~osed method.

Identification of clearances and stability analysis for a rotor-journal bearing system

“…The film thickness is given by superposition of film thicknesses as it is mentioned by Nikolakopoulos and Papadopoulos [5] and Dufranne et al [1], for the abrasive bearing wear model:…”

“…Nikolakopoulos and Papadopoulos [5] have examined the effects of the misalignments on the stability of a linear rotor-bearing system in laminar flow, via the direct method of Lyapunov.…”

Model and Algorithm for a Rotor-Bearing System Considering Journal Misalignment

“…The linear [15] and nonlinear [16][17][18] effects on the bearing characteristics caused by rotor disturbances were also researched. The axial motion [19][20][21] was also taken into consideration.…”

Inter-asperity cavitation for misalignment journal lubrication problem based on mass-conservative algorithm

“…The steady-state characteristics of a journal bearing in terms of load, attitude angle, oil leakage, frictional coefficient, and misalignment moment are estimated with various values of roughness parameters, misalignments, and eccentricity ratios. Nikolakopoulos (1994;1997;2008) presented an analysis of a misaligned journal bearing operating in linear and nonlinear regions. He also examined the effects of the misalignments on the stability of a linear rotorbearing system in laminar flow, via the direct method of Lyapunov.…”