Abstract Since the introduction of bender element tests to soil testing, the reliability of the estimated travel time has been the most serious problem. The author has previously shown a potential solution whereby removing the response of the bender element subsystem from the whole response could dramatically improve the accuracy of the travel time estimation. In order to lay the foundation for estimating the response of the bender element subsystem, this paper examines the correlation between the displacements of the element and the induced feedback signals by employing a self-monitoring element. The response of the self-monitoring element is modeled as a transfer function involving two internal transfer functions that relate the input signals to the displacements and the displacements to the feedback signals, respectively. Using a laser displacement sensor, the displacements are directly measured through the entire surface and reveal the three-dimensional bending motion of the element oscillating in both longitudinal and width directions. The feedback signals are similar to, but inconsistent with, the tip displacements, and an attempt is made to correct the feedback signals. Finally, a conclusion is given on the potential for estimating the response of the bender element subsystem using the self-monitoring element.

中文翻译：

---

源弯曲元件运动与自监测反馈信号的相关性

摘要 自从将弯曲单元测试引入土壤测试以来，估计走时的可靠性一直是最严重的问题。作者之前已经展示了一个潜在的解决方案，即从整个响应中去除弯曲单元子系统的响应可以显着提高旅行时间估计的准确性。为了为估计弯曲元件子系统的响应奠定基础，本文通过采用自监测元件检查了元件位移与感应反馈信号之间的相关性。自监控元件的响应被建模为一个传递函数，该传递函数涉及两个内部传递函数，它们分别将输入信号与位移和位移与反馈信号相关联。使用激光位移传感器，可以直接测量整个表面的位移，并揭示元件在纵向和宽度方向上振荡的三维弯曲运动。反馈信号与尖端位移相似但不一致，并尝试校正反馈信号。最后，对使用自监测元件估计弯曲元件子系统的响应的潜力给出了结论。