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.

了解骨质衰竭的起因对于评估骨折的进展和制定损伤标准至关重要。与传统方法相比，检测骨骼中的声发射可用于更敏感地识别骨折并在更早的时间识别骨折。但是，高速率加载条件，复杂的样本-设备交互作用或几何形状可能会导致其他声音信号。因此，表征来自皮质骨骨折的孤立局部声发射响应对于将其特性与其他潜在声源区分开来至关重要。这项工作开发了一种技术，该技术使用声发射信号通过同时使用Welch功率谱密度估计和连续小波变换进行表征来确定何时发生皮质骨衰竭。从胸椎椎体分离的皮质外壳标本（带有连接的声波传感器）经受准静态载荷直至失效。所产生的声发射具有宽带频率响应，其峰值范围为20至900 kHz，频谱峰值集中在三个频段（166±52.6 kHz，379±37.2 kHz和668±63.4 kHz）。使用这些频段，声发射可以用作生物力学脊柱测试中的监视工具，从而将骨衰竭与结构响应区分开。这项工作提出了一套必要的技术，可以有效地利用声发射来确定生物材料测试中皮质骨骨折的发作。使用提出的方法，可以为其他感兴趣的皮质骨区域开发声学特征。