Injury Biomechanics Laboratory. Department of Biomedical Engineering, Duke University, Durham, NC, USA.
Injury Biomechanics Laboratory. Department of Biomedical Engineering, Duke University, Durham, NC, USA.
J Biomech. 2021 Mar 5;117:110227. doi: 10.1016/j.jbiomech.2021.110227. Epub 2021 Jan 8.
Understanding the initiation of bony failure is critical in assessing the progression of bone fracture and in developing injury criteria. Detection of acoustic emissions in bone can be used to identify fractures more sensitively and at an earlier inception time compared to traditional methods. However, high rate loading conditions, complex specimen-device interaction or geometry may cause other acoustic signals. Therefore, characterization of the isolated local acoustic emission response from cortical bone fracture is essential to distinguish its characteristics from other potential acoustic sources. This work develops a technique to use acoustic emission signals to determine when cortical bone failure occurs by characterization using both a Welch power spectral density estimate and a continuous wavelet transform. Isolated cortical shell specimens from thoracic vertebral bodies with attached acoustic sensors were subjected to quasistatic loading until failure. The resulting acoustic emissions had a wideband frequency response with peaks from 20 to 900 kHz, with the spectral peaks clustered in three bands of frequencies (166 ± 52.6 kHz, 379 ± 37.2 kHz, and 668 ± 63.4 kHz). Using these frequency bands, acoustic emissions can be used as a monitoring tool in biomechanical spine testing, distinguishing bone failure from structural response. This work presents a necessary set of techniques for effectively utilizing acoustic emissions to determine the onset of cortical bone fracture in biological material testing. Acoustic signatures can be developed for other cortical bone regions of interest using the presented methods.
了解骨失效的起始对于评估骨骨折的进展和制定损伤标准至关重要。与传统方法相比，骨中的声发射检测可更灵敏、更早地识别骨折。然而，高率加载条件、复杂的标本-器件相互作用或几何形状可能会导致其他声信号。因此，对皮质骨骨折的隔离局部声发射响应进行特征描述对于将其特征与其他潜在声源区分开来至关重要。这项工作开发了一种使用声发射信号的技术，通过使用 Welch 功率谱密度估计和连续小波变换来确定皮质骨失效发生的时间。带有附加声传感器的胸椎体的分离皮质壳标本在准静态加载下直至失效。产生的声发射具有宽带频率响应，峰值在 20 至 900 kHz 之间，频谱峰值聚集在三个频带（166 ± 52.6 kHz、379 ± 37.2 kHz 和 668 ± 63.4 kHz）中。使用这些频带，声发射可作为生物力学脊柱测试中的监测工具，将骨失效与结构响应区分开来。这项工作提出了一套必要的技术，用于有效地利用声发射来确定生物材料测试中皮质骨骨折的起始。可以使用所提出的方法为其他感兴趣的皮质骨区域开发声信号。
