Experimental teaching design of wave propagation in structures based on flexural wave broadband focusing
[Objective]The"Propagation of Waves in Structures"course is a professional and theoretical basic course.However,the current courses in elastic waves are mainly based on traditional theoretical teaching,which contrasts the requirement of combining teaching and engineering and is not conducive to students'creativity.Pure theoretical teaching cannot allow students to intuitively understand various novel phenomena in elastic wave propagation and regulation.This article constructs a set of structural wave propagation experimental teaching systems with the purpose of enabling students to understand and master the basics of elastic waves.While studying theory,students can actively exert their subjective initiative,learn to independently design structural models,and conduct experimental verification work.[Methods]This article is based on the latest scientific research achievement of our team:"Broadband Focusing of Bending Wave"in the study of elastic wave metamaterials/metasurfaces and combined with the existing experimental platform to develop a set of experimental teaching systems for wave propagation in structures.First,through theoretical teaching,students can initially master the theoretical knowledge of the incidence,refraction,and focusing of bending waves at the interface in the theory of elastic wave propagation in structures.Then,using metaplates as the experimental objects,the experimental teaching system is introduced in detail.The composition,experimental principle,and experimental content are given.[Results]The experimental results show that when the incident frequencies are 6,7,and 8 kHz,a stable and high-quality bending wave Gaussian beam is formed in the incident area at 33.80,28.98,and 25.37 ms after the bending wave is excited,respectively.At 34.23,29.37,and 25.72 ms,the incident wave passes through the metasurface and is focused near the preset focus in the transmission region.Whether it is the incident area or the transmission area,the formed wave field is stable and consistent with the theoretical design.Using the wave propagation detection experimental system in structures constructed in this article,the propagation data of elastic waves in corresponding structures can be obtained conveniently and quickly.By changing the design parameters of the metastructure and the excitation parameters of the piezoelectric sheet,the application scope of the experimental teaching system can be further expanded to fields such as energy capture and acoustic radiation suppression,which has broad application prospects and practical value.[Conclusions]Experimental teaching practice shows that the development and use of this experimental system have enriched the teaching content of the wave propagation course in structures,allowing students to master the basic theory of wave propagation while exercising their scientific research thinking skills,and can enable students to further understand the propagation mechanism of waves in structures and master the experimental methods.The integrated development of course teaching and scientific research achievements is believed to play a positive role in exploring curriculum reform and talent training models under the background of"new engineering"construction.
scientific research achievementelastic waveexperiment teachingresearch and education integration
NETL
NSTL
万方数据
