VIBRATION LOCA1,IZATION AND TVAVli: CONVERSlON

.\II in~os t iga t ion of t h r free dynamics of nearly pcriodic disordered t r i ~ ~ i hea111s is presented. An exact wave transfer matrix nietliodo log ,~ is chosen in order t o examine t h e effects of slight disorder among the bays upon the propagation of waves and tlie t,ransmis\ion of vil)ration through t h e truss beam. It is shown tha t both free harmonic waves and nlodes of vibration t h a t extend througliout the ent.irr ordered st.rncture may become localitrd t o a few of tlic bays of t h r disordered truss beam. In order t o examine the intoractions among t h e various waves present in the structure, the co~~cr .p t of power flow is utilized as a scalar descriptor of localization. 1'11~ mecllanism of 1ocalizat.ion for this multi-coupled system ii I I I I I ~ I I richer and more complex than for mono-co~~plcd systems. Spc~ifically, the leakage of energy from the tvavc pair t h a t is most 211l)j('ct to localization t o wave pairs t h a t ace less prone t o locali~a t io l i is observed, suggesting t h a t localization is more difficult to achieve in mult i-coupled systems than in mono-coupled ones. .-\lsl~. localization occurs primarily a t higher frequencies, when individual s tructural members resonate. It does not occur for global b r n t l i ~ ~ g vi1)ratioll modes. These are believed t o be the first results on localizat,ion for multi-coupled nearly periodic structures. T h e wave conversion mcchanisnl evidenced here is a novel phenomenon that is prohahly characteristic of disorder effects in multi-coupled