ANALYSIS AND EXPERIMENT OF VIBRATION AND ACOUSTIC CHARACTERISTICS OF CARBON FIBER-REINFORCED PLASTIC PLATE WITH FIXED BOUNDARY CONDITIONS

摘要

Recently, the vibration characteristics and acoustic prediction of composite plates with various boundary conditions has been studied due to their favorable relation of weight to strength. This paper studies the vibration response and acoustic prediction of thin rectangular carbon fiber-reinforced plastic (CFRP) plates. The plate has clamped boundary condition for the four edges. The unidirectional rectangular carbon fiber-reinforced plastic (CFRP) plate is excited by a harmonic concentrated force. The excited point location is approximately the fourth point of the plate length due to avoid nodal point. Comparison of the natural frequency and mode shape between theoretical value and experimental data is conducted. Theory used in this paper is the classical plate theory (CPT) that is applicable to the thin plate (the CPT neglects the effect of the transverse shear deformation). Sound pressure is measured at 1m central point to compare the acoustic radiation characteristics. Rayleigh integral equation was used to predict the acoustic radiation characteristic. Finally, to verify the theoretical solution and value of experimental data, numerical solution is also obtained by FE tool. It is found that the peak levels of sound pressure occur only in non-symmetric vibration mode. Some peak also occurs in experiment at symmetric mode, because it does not implement the full symmetric mode practically.