非破壞性檢測的發展，改善了傳統檢測，並提高了效率，過往對於結構建物的安全檢測方法，大多都採用傅立葉轉換（Fourier Transform，FT）作為分析數值的方法，是由地震所激發出來的結構物反應訊號，從其時間域轉換成頻率域來觀察。傅立葉轉換是利用不隨時變的預設基底展開訊號，所以只適合處理線性、穩態的訊號，因而無法得到訊號瞬時變動的特性。在結構物的安全監測方面，要處理地震力這種非線性、非穩態的訊號，需要更完善的方法來進行分析。 希爾伯特-黃轉換（Hilbert-Huang Transform，HHT）是一個較突破的時頻域分析方法，它具備了後定基底以及局部隨適基底兩大特性，故適合處理非線性、非穩態的訊號。此方法可將原始訊號展開為時間域與頻率域上的能量分布情形，之後並進一步分析結構物的動態特質，讓其結構更加安全。 目前HHT SHM分析方法是以希爾伯特-黃轉換為核心，整合了若干個數值分析方法而成，再利用希爾伯特邊際譜擷取想要觀察之資訊，定義出結構物模態參數的資訊。 本研究使用有限元素軟體ABAQUS建立多樓層之鋼構模型，於基底施加地震加速度歷時，接著提取輸出之頂樓資料以HHT SHM方法進行分析，再將訊號轉換成希爾伯特時頻譜，並提取模態參數振動特性。之後比較不同模型之分析結果，探討材料參數改變對模態參數之影響，從中分為彈性段斜率折減、塑性段斜率折減來分析。更進一步分析結構物局部樓層柱子塑性斜率上折減，對於模態參數與趨勢的影響。 ;The development of non-destructive testing has improved traditional testing and increased efficiency. In the past, most of the safety testing methods for structures and buildings used Fourier Transformas as a method to analyze the vibration signal, which were induced by earthquakes. The structure response signal is converted from the time domain to the frequency domain for analysis. Fourier transform uses a prior base that does not change at any time to expand the signal, so it is only suitable for processing linear and stationary signals, and therefore cannot obtain the characteristics of instantaneous changes in the signal. In terms of safety monitoring of structures, to deal with the non-linear and nonstationary signals of seismic forces, a more complete method is needed for analysis. Hilbert-Huang Transform （HHT） is a breakthrough in time-frequency domain analysis. So suitable for processing nonlinear and nonstationary signal. This method can expand the original signal into the energy distribution in the time domain and the frequency domain, and then further analyze the dynamic characteristics of the structure to access the safety of the structure. The current HHT SHM analysis method is based on the Hilbert-Huang transformtion as the core and integrates several numerical analysis methods. The Hilbert marginal spectrum to extract the information that you want to observe and define information the modal parameters of the structure. This study uses the finite element software ABAQUS to build a multi-story steel structure model, applies seismic acceleration to the base, and then extracts the output top floor acceleration data on output for analysis using the HHT SHM method, and then converts the signal into the Hilbert time spectrum and extracts the model state parameter vibration characteristics. After comparing the analysis results of different models, the influence of material parameter changes on the modal parameters is discussed, and the analysis is divided into the slope reduction of the elastic section and the reduction of the plastic section of stress vs strain curre. Here we further analyze whether the reduction in the plastic slope of the local floor columns of the structure has an effect on the modal parameters and trends.
