换能器——质量加载型
一种理想化的 Langevin 换能器，其中：
- 压电陶瓷位于中央位置。
- 与两端质量块相比，压电陶瓷的质量被视为可忽略不计。
- 两端质量块被视为无限刚性（即振动过程中不产生应变）。
"在这些条件下，所有弹性能量都通过介电耦合，静态耦合系数与动态耦合系数完全相同。因此，基频模态没有泛音，且该等效电路从直流到接近组装换能器中一个或多个组成部件最低谐振频率的频率范围内均有效。"（Berlincourt[3]，第 246 页）这样的换能器可以精确地表示为一个集中参数弹簧-质量系统。
Transducer - mass loaded
An idealized Langevin transducer where:
- The ceramic is centrally located.
- The ceramic mass is considered negligible compared to the end masses.
- The end masses are considered infinitely rigid (i.e., no strain during vibration).
"Under these circumstances all elastic energy is dielectrically coupled and the static and dynamic coupling factors are identical. There are therefore no overtones of the fundamental mode and the equivalent circuit is valid from dc to frequencies approacing the lowest resonance frequency of one or more individual parts of the assembled transducer." (Berlincourt[3], p. 246) Such a transducer then can be represented exactly as a lumped spring-mass system.
