本研究主要是採用向量式有限元素法來模擬鋼筋混凝土結構之非線性行為，因此利用向量式有限元素法之平面固體元來模擬混凝土受力之後的幾何非線性行為，以及利用向量式有限元素法之一維桁架桿件元來模擬鋼筋材受力之後的情形，將上述結合，構成鋼筋混凝土結構之數值模擬分析體系；在材料模型選擇中，混凝土採用非線性彈性模型，以Darwin和Pecknold之等效應變模型加以描述混凝土於加載過程中之非線性行為，鋼筋材料模型採用雙折線裡想彈塑性模型；鋼筋混凝土之間以完全握裹來模擬其效應；本文之數值算例針對三個部分來做驗證，首先針對Drawin 和Pecknold[21]提出之混凝土非線性彈性模型進行驗證，確認對其理論應用之正確性，接著針對混凝土材料模型進行驗證，因此針對混凝土單軸試驗進行驗證；最後針對鋼筋混凝土進行驗證，藉由無箍筋之鋼筋混凝土簡支梁以及含箍筋之鋼筋混凝土簡支梁數值算例，來驗證鋼筋混凝土結構之非線性行為。透過一系列數值算例和實驗結果比較進行驗證，發現所開發之數值模擬程序確實可以有效的模擬鋼筋混凝土結構之非線性行為。 A novel motion analysis method so called Vector Form Intrinsic Finite Element (VFIFE) method was used to simulate the nonlinear behavior of reinforced concrete. Two-dimensional solid finite elements are used to model the concrete, and truss elements are used to model the steel reinforcements. An equivalent uniaxial strain model that can characterize the nonlinear monotonic loading behavior of concrete material by Darwin and Pecknold is applied. The elastic-plastic response of reinforcement is considered in the analysis. Concrete and reinforcing bars are represented by separate material model which are combine together with a model of the interaction between reinforcing bar and concrete through perfect bond to describe the behavior of the composite reinforced concrete material. In this study, there are three parts to verify the accuracy and effectiveness of this simulation code. The investigation first considers the development of a consistent material model that matches the analytical model made by Darwin and Pecknold. In the second part, VFIFE calculations are compared with experimental results for the behavior of concrete under monotonic, uniaxial and biaxial loadings. Finally, the composite material model is compared with experimental results for a simply supported unconfined reinforced concrete beam and a simply supported confined reinforced concrete beam. Numerical examples demonstrate that the nonlinear responses for RC structures can be effectively analyzed by the proposed equivalent uniaxial strain model of concrete.
