動力學作業(yè)阻尼

1、佪乬XUq 對佪乬XUq 對UT ii 偠121, 2 , +2 = +2 =1222(22 21 ( 212 2 中 模態(tài)阻尼的用, 對乬結MCK對乬結MCK對 MK1C = CK1M, CM1K = KM1C, KC1M = MCK 阻尼對M CM 種(M1C)(M1K) = 中種偠用比尼對乬 復模態(tài) 的振動對乬 復模態(tài) 的振動 態(tài)中0M0 0MC+=KX 態(tài)中態(tài)的 態(tài)的 = 態(tài)中的振動X0M00+=特乬B = 特乬B = , =1 TA = TB =復模態(tài) 2n復模態(tài) 的Apz+Bpz=阻尼的來源與種The ingmaybeinherent inastructureor阻尼的來源與種Th

2、e ingmaybeinherent inastructureora dlmeaning:itnowappearstomean ing,andcannotbe used tomeantheinginstructure,whateveritsform,as thenamewouldDinginconventionaledmetalstructuresisduetohysteresishemetalitself,butoreof frictionatboltedorriveteds, andfluid,oftenjusthe阻尼Viscoelasticmaterials,suchaselastom

3、ers(rubber-materials),canbe阻尼Viscoelasticmaterials,suchaselastomers(rubber-materials),canbeformulatedtohaverelativelydmanufactureofvibrationisolators,enginemounts, Theingmaybeyaddedtoa arediscreteunits,usually usingfluids,suchasdersandviscoelasticinglayers 阻尼的來源與種The ingcanbecreatedbythefluid阻尼的來源與種

4、The ingcanbecreatedbythefluidaroundstructure,forflowle airorwater.Ifthere isnoonly dingsible,andtheenergy lossisdueto beimportant,butfornormalstructuresvibratinginradiationingcanusuallybeignored.Onthehand,ifrelativefluidflowis involved, forleaircraftwingtravelingthroughtheair,aerodynamicing(andstiff

5、ness)may阻尼DThe ingcanbegenerated阻尼DThe ingcanbegeneratedbymagneticingeffect ofaconductormovingina asusedin loudspeakers and,oferest,vibrationtesting,inelectro-magneticexciters,cansurprisinglylargeing .阻尼g(x)=Coulombg(x阻尼g(x)=Coulombg(x)= LinearvelocityVelocitysquaredervelocityg(x) = iStructural ing/

6、Hysteretic 阻尼系the ingforceisproportionalto阻尼Linearvelocityx+2nx +2x=阻尼Linearvelocityx+2nx +2x=n動與 1= (12)2 +(2)x+2(1+i)x = n動與1=(12)2 +阻尼比阻尼比阻尼的特性(c2 = , c1 = 各種(各種(Adams and Askenazi, 粘性粘性結構結構粘性阻尼與結構阻粘性阻尼與結構阻尼粘性阻尼與結構阻粘性阻尼與結構阻尼復模態(tài)的應復模態(tài)復 用的ing復模態(tài)的應復模態(tài)復 用的ingchashelicopterrotors, couplingnthecanleadtoAircraftysisandresponsecalculationsthepmethod,wherelargecross-fromaerodynamicingtermscaned chasvehicles where hydraulicersmaycouplethe sea-bedingcan belarge inrelation tof 復模態(tài)的應中特對結構系統(tǒng)復模態(tài)的應中特對結構系統(tǒng)復模態(tài) 模態(tài) Inastructure, theingtermstendtobesm