KUO-CHIH CHUANGZhang, ZhiqiangZhiqiangZhangWang, HuaxinHuaxinWang2025-09-242025-09-242016https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992488152&doi=10.1016%2Fj.physleta.2016.09.055&partnerID=40&md5=04cf1e668457adf3fff07cc1b0cc34fchttps://scholars.lib.ntu.edu.tw/handle/123456789/732402This work experimentally studies influences of the point defect modes on the group velocity of flexural waves in a phononic crystal Timoshenko beam. Using the transfer matrix method with a supercell technique, the band structures and the group velocities around the defect modes are theoretically obtained. Particularly, to demonstrate the existence of the localized defect modes inside the band gaps, a high-sensitivity fiber Bragg grating sensing system is set up and the displacement transmittance is measured. Slow propagation of flexural waves via defect coupling in the phononic crystal beam is then experimentally demonstrated with Hanning windowed tone burst excitations.Band GapsDefect ModesFiber Bragg Gratings (fbgs)Flexural WavesPhononic CrystalsCrystalsElastic WavesEnergy GapFiber Bragg GratingsLight VelocityPhononsTransfer Matrix MethodDefect ModeFiber Bragg Grating Sensing SystemFiber Bragg Gratings (fbgs)High SensitivityLocalized DefectsPhononic CrystalPoint-defect ModesSupercell TechniqueDefectsjournal article10.1016/j.physleta.2016.09.0552-s2.0-84992488152