Fracture mechanisms of quasi-brittle materials based on acoustic emission
Fracture mechanisms of quasi-brittle materials based on acoustic emission
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DOI：
10.1557/jmr.1990.0206
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发表时间：
1990-01
影响因子：
2.7
通讯作者：
A. Maji;C. Ouyang;S. Shah
中科院分区：
文献类型：
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作者：
A. Maji;C. Ouyang;S. Shah
近年来，声发射（AE）技术被用于研究材料的裂纹扩展。将这些技术应用于非均质、准脆性材料，如混凝土，需要更好地理解微断裂产生的信号是如何由于波传播和换能器响应而转换的。在本研究中，压电换能器使用位移传感器进行校准。对水泥基材料的弹性动力学格林函数方法的有效性进行了检验。利用矩张量分析对声发射源进行了表征。对砂浆和混凝土中裂板试件的声发射测量进行了分析。观察到，正如预期的那样，开裂的主要模式是I型（拉伸）。然而，II型（剪切）和混合模式裂纹也发生，可能是由于晶界滑动和界面脱粘。微断裂在临界裂纹扩展之前出现局部化。I型裂纹通常比II型裂纹需要更多的能量释放，较小的夹杂物比较大的夹杂物提供更强的界面结合。
Recently acoustic emission (AE) techniques have been used to study crack propagation in materials. The application of these techniques to heterogeneous, quasi-brittle materials such as concrete requires a better understanding of how the signal generated from a microfracture is transformed due to wave propagation and due to the transducer response. In this study, piezoelectric transducers were calibrated using displacement transducers. The validity of an elastodynamic Green’s function approach was examined for cement-based materials. The acoustic emission source was characterized using moment tensor analysis. Acoustic emission measurements were analyzed for center-cracked-plate specimens of mortar and concrete. It was observed that, as expected, the dominant mode of cracking was mode I (tensile). However, mode II (shear) and mixed mode cracks also occurred, perhaps due to grain boundary sliding and interface debonding. Microfractures appear to localize prior to critical crack propagation. Mode I cracks generally required more energy release than mode II and a smaller inclusion provided a stronger interface bond than the larger ones.