ABSTRACT Characterization of dolomitic limestone rock samples with increasing levels of damage is presented using a nonlinear ultrasonic approach. Limestone test samples with increasing levels of damage were created artificially by exposing virgin samples to increasing temperature levels of 100, 200, 300, 400, 500, 600, and 700°C for a ninety minute period of time. These samples were first characterized using ultrasonic dilatational and shear phase velocity measurements and corresponding attenuations. Then, a nonlinear approach based upon noncollinear wave mixing of two dilatational waves was used. Criteria were used to assure that the detected scattered wave originated via wave interaction in the limestone and not from nonlinearities in the testing equipment. It was observed that both the dilatational velocity and the noncollinear wave mixing approach are able to characterize the level of damage in limestone rock. However, the nonlinear approach is more sensitive to damage accumulation by about two orders of magnitude.

中文翻译：

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石灰石的非线性超声损伤表征

摘要 使用非线性超声方法对损伤程度不断增加的白云质石灰岩样品进行表征。通过将原始样品暴露在 100、200、300、400、500、600 和 700°C 的不断升高的温度水平 90 分钟时间段内，人为地创建了损坏程度不断增加的石灰石测试样品。这些样品首先使用超声膨胀和剪切相速度测量以及相应的衰减进行表征。然后，使用基于两个膨胀波的非共线波混合的非线性方法。使用标准来确保检测到的散射波源自石灰石中的波相互作用，而不是源自测试设备中的非线性。据观察，膨胀速度和非共线波混合方法都能够表征石灰岩中的损坏程度。然而，非线性方法对损伤累积更敏感大约两个数量级。