Development of vibration absorbing device utilizing chaotic vibrations of buckled curved plate for reduction of low-frequency sound

Research Project

Project/Area Number	16K06145
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Dynamics/Control
Research Institution	Gunma University
Principal Investigator	Nagai Ken-ichi 群馬大学, その他部局等, 名誉教授 (00110403)
Co-Investigator(Kenkyū-buntansha)	丸山真一群馬大学, 大学院理工学府, 准教授 (60344925)
Project Period (FY)	2016-04-01 – 2019-03-31
Project Status	Completed (Fiscal Year 2018)
Budget Amount *help	¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000) Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000) Fiscal Year 2017: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000) Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Keywords	非線形振動 / 機械力学・制御
Outline of Final Research Achievements	Aiming at developing a low-frequency sound-absorbing device utilizing chaotic vibrations of a buckled curved plate accompanied by dynamic snap through transition, experiments are conducted on nonlinear vibrations of a rectangular unsymmetrically laminated CFRP plate. The CFRP plate is fixed at center with bolts. The CFRP plate has two stable equilibrium configurations which is an upward convex and a downward convex. The CFRP plate is exited with periodic acceleration by an electromagnetic shaker. Sweeping the excitation frequency, responses of the plate are measured by laser displacement sensors. In a specific condition of fiber orientation with respect to the rectangular boundary and attached concentrated masses, it was shown that chaotic vibrations are induced accompanied with dynamic snap-through transition.
Academic Significance and Societal Importance of the Research Achievements	非対称積層CFRP板に動的飛び移りを伴うカオス振動が生じる条件を明らかにすることで，広帯域の低周波音と簡素な仕組みで吸音できる装置への応用可能性が飛躍的に高まった．