为了解决宇称-时间（Parity-Time，PT）对称结构存在结构复杂、奇异点难以调谐的 问题，基于压电分流技术，设计一种针对弯曲波的PT对称梁. 推导PT对称条件，基于等效介质 法和有限元法，验证所设计增益单元、损耗单元的等效参数满足该PT对称条件，并通过改变谐 振频率和分流电阻研究了奇异点的可调性. 通过传递矩阵法和有限元法，对PT对称梁的散射 特性进行分析，讨论单向无反射点与奇异点之间的关系. 理论计算和仿真结果表明，PT对称梁 有包括511 Hz和520.5 Hz在内的多个奇异点. 弯曲波频率为511 Hz的弯曲波从右端入射时反 射系数趋于零，而弯曲波频率为 520.5 Hz时，它必须施加在左端从而达到完全透射而不产生 反射.
To solve the problems of complex structure and difficulty in tuning the exceptional points in the exist? ing PT-symmetric structures, a PT-symmetric beam for flexural waves is designed based on piezoelectric shunting technology. Firstly, the PT-symmetric condition is derived. Then, based on the effective medium method and finite el? ement simulation, it is verified that the effective parameters of the gain and loss unit meet the PT-symmetric condi? tion, and the tunability of exception points is studied by changing the resonant frequency and the shunting resistance. Finally, the scattering property of the PT-symmetric beam is derived by the transfer matrix method and finite element simulation, and the relationship between exceptional points and unidirectional non-reflection is illustrated. The cal? culated and simulated results show that the PT-symmetric beam has several exceptional points including 511 Hz and 520.5 Hz. When the incident flexural wave of 511 Hz is applied at the right side of the PT-symmetric beam, the re? flection coefficient is close to zero. However, when the frequency of the incident flexural waves changes to 520.5 Hz， it should be applied on the left side of the PT-symmetric beam to gain an entire transmission without reflection.
王刚 ,罗彩明 ,张晓东.基于压电分流技术的PT对称梁散射特性研究[J].湖南大学学报：自然科学版,2022,49(8):61~71复制