Abstract The microstructural features of heterogeneous and porous materials give rise to unique non-linear dynamic behaviour. The purpose of this work is to investigate the dynamic response of thermally damaged concrete specimens measured by two different techniques: Non-linear Impact Resonance Acoustic Spectroscopy (NIRAS) and new Flipped Accumulative Non-linear Single Impact Acoustic Spectroscopy (FANSIRAS). Specimens were characterised in two different dynamic condition states of the material: relaxed and conditioned. The specimen’s relaxed state indicates that no previous dynamic excitation event ocurred. The conditioned state denotes that the specimen has been dynamically tested before. The NIRAS results show that the non-linear material parameters, α f and α Q , are affected by their previous dynamic history (its conditioning). The recently proposed algorithm, FANSIRAS, extracts from a single resonant signal equivalent results to NIRAS when the specimen is conditioned. In this situation, both parameters α f and α Q were equivalent. The results suggest that new NDT parameters based on non-linear hysteretic parameters can quantify the damage level of thermally treated mortar specimens.

中文翻译：

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慢动力学和调节对使用冲击共振声谱法进行非线性滞后材料评估的影响

摘要 异质多孔材料的微观结构特征产生了独特的非线性动态行为。这项工作的目的是研究通过两种不同技术测量的热损坏混凝土试样的动态响应：非线性冲击共振声谱 (NIRAS) 和新的翻转累积非线性单次冲击声谱 (FANSIRAS)。样品在材料的两种不同动态状态下进行表征：松弛和调节。标本的松弛状态表明没有发生先前的动态激发事件。条件状态表示试样之前已经过动态测试。NIRAS 结果表明，非线性材料参数 α f 和 α Q 受其先前动态历史（其调节）的影响。最近提出的算法 FANSIRAS 从单个共振信号中提取等效于 NIRAS 的结果，当样本处于调节状态时。在这种情况下，参数α f 和α Q 是等效的。结果表明，基于非线性滞后参数的新 NDT 参数可以量化热处理砂浆试样的损伤水平。