The structural integrity of corroded reinforced concrete (RC) elements is commonly evaluated by the electrical resistivity method to estimate only the mass loss of reinforcement. It is also possible to evaluate overall deterioration induced by corrosion in the RC elements by examining their nonlinear dynamic behaviors. Therefore, herein, a nonlinear vibration-based diagnostic technique is investigated to measure the magnitudes of higher harmonics of resonance caused due to the corrosion-induced damage in the reinforced concrete. The developed diagnostic technique utilizes an adaptive higher order spectral analysis, which incorporates the wavelet transform instead of the Fourier transform, in order to suit the transit vibration signals generated under an impact hammer. Initially, the algorithm to extract a diagnostic feature, named the wavelet transform-based bicoherence (WTB), is developed on the synthetic vibration signals with different levels of nonlinearity. Then, the developed diagnostic method is demonstrated on two lab-scale RC columns. Comparison of the results obtained by the traditional Fourier-based and the proposed wavelet-based bispectra reveals up to 42.7% improvement in the discrimination of the damaged column from the intact one.

中文翻译：

---

基于非线性振动的钢筋混凝土腐蚀引起的劣化评估

通常通过电阻率方法评估腐蚀的钢筋混凝土（RC）单元的结构完整性，以仅估计钢筋的质量损失。还可以通过检查RC元件的非线性动力学行为来评估其腐蚀引起的整体劣化。因此，本文中，研究了一种基于非线性振动的诊断技术，以测量由于钢筋混凝土中的腐蚀引起的损伤而引起的共振的高次谐波的大小。所开发的诊断技术利用自适应高阶频谱分析，该分析结合了小波变换而不是傅立叶变换，以便适应在冲击锤下产生的瞬态振动信号。最初，用于提取诊断特征的算法 基于小波变换的双相干性（WTB）是针对具有不同非线性程度的合成振动信号而开发的。然后，在两个实验室规模的RC色谱柱上展示了开发的诊断方法。对传统的基于傅立叶的和建议的基于小波的双谱所获得的结果进行比较，发现从完整的色谱柱对损坏的色谱柱的辨别性方面最多可提高42.7％。