Acoustic Black Hole Curved Beam Structure Piezoelectric Vibrator Energy Capture Performance Study

Vibration energy is a common form of energy in nature,and it has been the focus of research scholars on how to capture it efficiently.Acoustic black hole(ABH)as an efficient bending wave manipulation technique has been shown to have great potential for energy capture applications.In the acoustic black hole structure,when the thickness of the structure gradually decreases to zero,the velocity of the bending wave rapidly decreases,the amplitude increases,the phase accumulates,and there is no emission at the edge of the structure,forming a local energy accumulation that provides a basis for energy capture.Currently,the research on energy capture of acoustical black hole mainly focuses on straight beam or flat plate structure.In practical engineering,especially in the field of Aeronautics and navigation,curved beam and crank shell structure also exist extensively,but at present,the research on embedding ABH structure into the crank beam and its energy capture characteristics is still insufficient.In view of the above shortcomings,this paper combines the acoustical black hole effect with the curved beam structure,proposes a piezoelectric energy capture model based on the acoustical black hole curved beam,and comprehensively studies the vibration and energy capture characteristics of the structure by semi-analytical method and numerical simulation method.The main research contents of this paper are as follows:(1)A structure that embeds acoustic black holes into a curved beam(ABH curved beam structure)is proposed.Based on the Rayleigh-Ritz theory,a modal analysis model is established for the ABH curved beam structure,and the dynamic characteristics and energy aggregation characteristics of the ABH curved beam are analyzed in detail to provide a theoretical basis for the energy capture of the structure.The coupling problem between the piezoelectric element and the main structure is flexibly handled by the energy term,and a semi-analytical model is established for the analysis of the dynamic characteristics and energy capture characteristics of the ABH curved beam piezoelectric energy capture system.The semi-analytical model is validated by calculating the modal parameters and energy conversion power of the structure by means of finite element numerical simulation.The advantages and disadvantages of the semi-analytical model and the finite element numerical simulation proposed in this paper are further analyzed,as well as their applications.(2)Based on the semi-analytical model,the energy capture effects of ABH curved beam and uniform curved beam in the frequency domain are compared.Compared with the uniform bending beam,the ABH bending beam energy capture system overcomes the dependence of the traditional energy capture structure on individual frequencies and resonant frequencies,and has outstanding energy capture performance in the wide frequency range.For the wavelength compression effect inside the ABH,the piezoelectric sheet layout is reasonably set to solve the problem of weakened energy capture efficiency in the middle and high frequencies of the system.The effects of load resistance,piezoelectric material and structural curvature on the system are analyzed in detail,and conclusions and suggestions for improving the energy capture capability are obtained.(3)The problem that the structural stiffness of the curved beam is weakened by the embedded acoustic black hole is considered.On the basis of the ABH curved beam,optimization is carried out by adding reinforcement,and the effects of the thickness and layout of the reinforcement on the structural stiffness are analyzed in detail.The results show that the stiffness of the curved beam can be effectively improved by increasing the thickness of the reinforcement,while for the two reinforcement bars,the use of uniform distribution is more conducive to suppressing the vibration deformation of the structure in the middle and high frequencies...