應力波法在挫屈束制消能支撐非破壞檢測之應用

Abstract

本研究之主旨就在於利用非破壞檢測中的應力波法，對高層結構所採用之消能桿件—挫屈束制支撐進行檢測，並發展出適當的訊號分析步驟，以評估受地震作用後挫屈束制支撐的完整性。 本計畫先以數值模擬進行研究。數值模擬是利用LS-DYNA程式進行有限元素分析，計算支撐核心元件受敲擊後之波傳反應。數值模擬中將考慮數種不同程度的破壞，並分析各種破壞狀況的反應訊號。訊號分析方法則採用了時間域、傅利葉分析、小波分析以及希爾伯-黃分析。模型試驗係配合國家地震工程研究中心「實尺寸兩層樓挫屈束制支撐子結構雙向受震擬動態試驗與分析」計畫進行測試，在結構未受震及四次振動台試驗後，對挫屈束制支撐進行應力波試驗，以觀量測訊號的變化。最後，將以模擬訊號和實驗訊號驗證訊號分析方法的可行性。

The motive of this research is to use one of the nondestructive testing methods, stress wave method, to test the energy dissipation element, buckling restrained brace (BRB), which is used in high-rise structures. In this project, we implement the numerical simulations first. We make use of the commercial software, LS-Dyna, to process the finite element analysis and calculate the wave propagation responses of the core element in the BRB. In numerical simulations, we consider different levels and positions of the defects, and analyze the response signals of different damage conditions. We use time domain analysis, Fourier analysis, Wavelet analysis, and Hilbert-Huang analysis as our signal process methods. We hope that we can get some damage index which can show the damage level efficiently. Second, we operate the NDT method in coordination with another experiment about the BRB executed by National Center of Research on Earthquake Engineering (NCREE). The BRB specimen will sustain several sets of ground acceleration. We process the NDT method and measure the signals after the BRB sustained each set of ground acceleration, and observe the change of the signal measured indifferent stage. Finally, we use simulated and experimental signals to confirm the feasibility of the signal process method.