- 學位論文
含溫度效應之有限梁元素幾何非線性分析
Geometric Nonlinear Analysis of Structures Using Beam Elements Considering the Thermal Effect
摘要
臺灣地處環太平洋地震帶，頻繁的地震運動，著實對臺灣人民的生命財產損失，以及心中的恐懼，有著難以估算的影響。因此，鑒於建築結構耐震的需求，近年來，臺灣地區興起了一陣鋼骨結構的風潮。鋼結構擁有質輕和耐震性佳的優點，對地震運動旺盛的臺灣而言，的確是良好的建築方式之一。 但是比起傳統的鋼筋混凝土，鋼結構對溫度的敏感度大為提高。火災發生時，其帶來的高溫常伴隨著鋼材性質的劣化，諸如彈性模數與降伏應力的折減、變形量及偏心量增大、結構強度及承載能力下降。換句話說，在火害中，鋼結構所受的影響實是嚴重許多。故溫度對結構物的影響必須受到相當程度的重視。 倘若以傳統線性理論分析相關問題，並無辦法完全反應實際火害發生的情況。故此，本文企圖從力學的角度切入，並引用非線性的分析方法，探討材料受火害前後力學行為的差異，先以靜定懸臂梁為分析例，再建立起有限梁元素的模型，希望能對結構受溫度效應作用之後的行為，能有更深入的認知與了解。最後，期許能發展出一套建築結構受火害的分析流程，未來能針對相關的問題作分析。也希望所得的結果可以作為未來防火設計準則和規範制定時的參考。
並列摘要
The objective of this thesis is to investigate the behavior of steel frames in high temperature. In the past decades, steel has been popularly used as a constructional material. Compared with other commonly used materials, such as reinforced concrete, steel has a high thermal conductivity and softens rapidly when the temperature reaches a certain level, which makes the behavior of a steel structure in fire drastically different from that at room temperature. Therefore, geometrical nonlinearity caused by large deformations, material nonlinearity caused by softening, and the effect of thermal straining on the calculation of member forces should all be taken into account in analysis. In this thesis, the analytical solution of cantilever beam under high temperature conditions will be derived by the total Lagrangian formulation. This solution can be used as a benchmark solution for comparison with the solutions obtained by the finite element method. Further, a finite element considering the thermal effect is formulated to simulate the inelastic nonlinear behavior of steel beams in high temperature. From the design point of view, the overall capacity of a steel frame can be well represented by the critical load-temperature curves.
參考文獻
延伸閱讀
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