改進局部柔度法於梁結構損傷診斷之研究

A Study on Damage Detection of Beam Structures Using the Pseudo Local Flexibility Method

許丁友(Ting-Yu Hsu) ； 蕭勝元(Shen-Yuan Shiao) ； 廖文義(Wen-I Liao)

《結構工程》 29卷4期 (2014/12) Pp. 5-18

https://doi.org/10.6849/SE.201412_29(4).0001

摘要

局部柔度法（Local flexibility method）主要是藉由量測模態參數便可判斷梁結構之局部剛度變化。該方法基本條件之一，係使用一虛力使其所導致之應力在局部結構區域不為零，其他區域為零；本研究提出擬局部柔度法（Pseudo local flexibility method），係打破此一基本條件，使其使用之虛力導致應力在局部結構區域產生集中應力，並於其他區域也有微小應力。本研究將擬局部柔度法應用於超靜定梁結構上，且利用數值模擬與實際試驗進行驗證，結果顯示，擬局部柔度法於少量模態的情況下，能更準確地診斷超靜定梁結構之損傷位置及程度。

關鍵字

局部柔度法 ； 擬局部柔度法 ； 梁結構 ； 損傷診斷 ； 健康診斷

並列摘要

The local flexibility method, which can determine local stiffness variations of beam structures by using measured modal parameters, is one of the more promising vibration-based approaches. The local flexibility method is founded on ＂local＂ virtual forces that cause nonzero stresses within a local part of the structure. In this study, this basic rule has been broken. The ＂pseudo-local＂ virtual forces that cause concentrated stresses in a local part and nonzero stresses in the other parts of a structure are employed. The theoretical basis of the proposed ＂pseudo local flexibility method＂ (PLFM) is derived. The effects of the number of modes on the damage detection results are studied using both numerical and experimental hyper-static beam models. The results show that significantly fewer modes are required for the PLFM to estimate the damage location and extent with acceptable accuracy. Therefore, the feasibility of the PLFM is higher because only a limited number of high quality modes can be identified in real world applications.

並列關鍵字

Pseudo local flexibility method ； beam structure ； damage detection ； health monitoring