动力学作业阻尼

1、佪乬XUq 对佪乬XUq 对UT ii 偠121, 2 , +2 = +2 =1222(22 21 ( 212 2 中 模态阻尼的用, 对乬结MCK对乬结MCK对 MK1C = CK1M, CM1K = KM1C, KC1M = MCK 阻尼对M CM 种(M1C)(M1K) = 中种偠用比尼对乬 复模态 的振动对乬 复模态 的振动 态中0M0 0MC+=KX 态中态的 态的 = 态中的振动X0M00+=特乬B = 特乬B = , =1 TA = TB =复模态 2n复模态 的Apz+Bpz=阻尼的来源与种The ingmaybeinherent inastructureor阻尼的来源与种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 阻尼的来源与种The ingcanbecreatedbythefluid阻尼的来源与种

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动与 1= (12)2 +(2)x+2(1+i)x = n动与1=(12)2 +阻尼比阻尼比阻尼的特性(c2 = , c1 = 各种(各种(Adams and Askenazi, 粘性粘性结构结构粘性阻尼与结构阻粘性阻尼与结构阻尼粘性阻尼与结构阻粘性阻尼与结构阻尼复模态的应复模态复 用的ing复模态的应复模态复 用的ingchashelicopterrotors, couplingnthecanleadtoAircraftysisandresponsecalculationsthepmethod,wherelargecross-fromaerodynamicingtermscaned chasvehicles where hydraulicersmaycouplethe sea-bedingcan belarge inrelation tof 复模态的应中特对结构系统复模态的应中特对结构系统复模态 模态 Inastructure, theingtermstendtobesm