The application of absolutely calibrated piezoelectric (PZT) sensors is increasingly used to help interpret the information carried by radiated elastic waves of laboratory/in situs acoustic emissions (AEs) in nondestructive evaluation. In this paper, we present the methodology based on the finite element method (FEM) to characterize PZT sensors. The FEM-based modelling tool is used to numerically compute the true Green’s function between a ball impact source and an array of PZT sensors to map active source to theoretical ground motion. Physical-based boundary conditions are adopted to better constrain the problem of body wave propagation, reflection and transmission in/on the elastic medium. The modelling methodology is first validated against the reference approach (generalized ray theory) and is then extended down to 1 kHz where body wave reflection and transmission along different types of boundaries are explored. We find the Green’s functions calculated using physical-based boundaries have distinct differences between commonly employed idealized boundary conditions, especially around the anti-resonant and resonant frequencies. Unlike traditional methods that use singular ball drops, we find that each ball drop is only partially reliable over specific frequency bands. We demonstrate, by adding spectral constraints, that the individual instrumental responses are accurately cropped and linked together over 1 kHz to 1 MHz after which they overlap with little amplitude shift. This study finds that ball impacts with a broad range of diameters as well as the corresponding valid frequency bandwidth, are necessary to characterize broadband PZT sensors from 1 kHz to 1 MHz.

绝对校准压电 (PZT) 传感器的应用越来越多地用于帮助解释实验室/原位声发射 (AE) 的辐射弹性波在无损评估中携带的信息。在本文中，我们提出了基于有限元法 (FEM) 来表征 PZT 传感器的方法。基于 FEM 的建模工具用于数值计算球撞击源和 PZT 传感器阵列之间的真实格林函数，以将活动源映射到理论地面运动。采用基于物理的边界条件来更好地约束体波在弹性介质中/上的传播、反射和传输问题。该建模方法首先根据参考方法（广义射线理论）进行验证，然后扩展到 1 kHz，其中探索了沿不同类型边界的体波反射和传输。我们发现使用基于物理的边界计算的格林函数在常用的理想化边界条件之间存在明显差异，尤其是在反谐振和谐振频率附近。与使用单一落球的传统方法不同，我们发现每个落球在特定频段上仅部分可靠。我们通过添加频谱约束证明，单个仪器响应在 1 kHz 到 1 MHz 范围内被准确裁剪并链接在一起，之后它们以很小的幅度偏移重叠。