【摘要】：由于組成預應力鋼筋混凝土的材料自身存在非線性，用彈性力學手段來分析和研究預應力鋼筋混凝土結構滿足不了實際工程對精度的要求。采用非線性方法進行分析已經成為主流趨勢，本文將采用OpenSEES纖維模型分析鋼筋混凝土結構材料非線性，因為OpenSEES這個軟件本身存在的優(yōu)點能夠克服非線性方程組求解過程中穩(wěn)定性和精確性不夠的缺點，此外建立纖維模型可以將構件截面劃分，從而同一截面的不同纖維可以有不同的單軸應力應變關系，這樣就可以采用更加符合構件受力狀態(tài)的單軸本構關系，更好的模擬鋼筋和混凝土之間的實際工作性能，，經過數(shù)值模擬和實際工程試驗對比分析得出，OpenSEES具有較好的非線性數(shù)值模擬精度和優(yōu)越性。主要的研究內容如下： 1、將OpenSEES軟件應用到橋梁結構來數(shù)值模擬材料非線性，闡述OpenSEES軟件分析結構非線性的具體過程，包括模型建立、進行非線性分析到結果輸出。 2、以鋼筋混凝土簡支梁單梁為例子，研究用TCL編程方法編輯OpenSEES命令流，在不斷增加荷載等級直到結構破壞，分析整個加載過程中荷載和跨中位移以及受拉區(qū)縱向鋼筋應力隨荷載等級的變化過程，并分別用能量等效面積法和通用屈服彎矩法兩種方法確定構件的屈服點。 3、以預應力鋼筋混凝土簡支梁橋為例子，通過用ETABS建模、OpenSEES前處理接口ETO處理生成TCL腳本文件，導入OpenSEES軟件分析，研究用剛臂的方法模擬預應力鋼筋纖維和混凝土纖維之間的連接，得出加載過程中荷載和跨中位移的變化曲線以及普通梁和預應力梁荷載位移曲線的對比分析。 4、以多梁式簡支T梁為例子，建立體系的纖維單元，通過偏載、中載、均勻加載三種方式，分析各梁的材料非線性變化過程。在偏載加載方式下，數(shù)值模擬的各梁荷載位移數(shù)據分別與破壞性試驗數(shù)據進行了對比分析，結果相吻合。此外還研究了三種工況下各梁的極限承載能力及受拉區(qū)縱向鋼筋隨荷載等級的變化，各梁通過對比分析確定鋼筋的屈服點。 綜上所述，通過實例分析表明OpenSEES軟件分析非線性不但分析精度高，而且前處理可具有較高的操作性，說明用OpenSEES軟件分析材料非線性具有優(yōu)越性，可以為其他非線性分析提供參考價值。
[Abstract]:Due to the nonlinearity of the materials which make up the prestressed reinforced concrete, the analysis and study of the prestressed reinforced concrete structures by means of elastic mechanics can not meet the requirements of the actual engineering precision. It has become a mainstream trend to use nonlinear method to analyze the material nonlinearity of reinforced concrete structures. In this paper, OpenSEES fiber model is used to analyze the nonlinearity of reinforced concrete structures. Because of the advantages of OpenSEES software, it can overcome the shortcomings of the stability and accuracy in solving the nonlinear equations. In addition, the fiber model can be used to divide the cross-sections of the components. Thus, different fibers of the same section can have different uniaxial stress-strain relationships, so that the uniaxial constitutive relationship, which is more consistent with the stress state of the members, can be used to simulate the actual working performance between steel bars and concrete. Through the comparison and analysis of numerical simulation and practical engineering test, it is concluded that OpenSEES has good accuracy and superiority in nonlinear numerical simulation. The main research contents are as follows: 1. The OpenSEES software is applied to the bridge structure to simulate the material nonlinearity, and the concrete process of analyzing the nonlinear structure by OpenSEES software, including the modeling, is expounded. The nonlinear analysis is carried out to the result output. 2. Taking the single beam of reinforced concrete simply supported beam as an example, the TCL programming method is used to edit the OpenSEES command stream, and the load grade is continuously increased until the structure is destroyed. The variation process of load, mid-span displacement and longitudinal steel bar stress with load grade during the whole loading process is analyzed. The energy equivalent area method and the general yield moment method are used to determine the yield point of the member. 3. Taking the prestressed reinforced concrete simply supported beam bridge as an example, the TCL script file is generated by using ETABS modeling and OpenSEES pre-processing interface ETO processing. This paper introduces OpenSEES software to analyze the connection between prestressed steel fiber and concrete fiber with the method of rigid arm. The variation curves of load and mid-span displacement and the load-displacement curves of common beam and prestressed beam are compared and analyzed. 4. Taking multi-beam simply supported T-beam as an example, the fiber element of the system is established. Three ways of uniform loading are used to analyze the material nonlinear variation process of each beam. Under the eccentric loading mode, the load and displacement data of each beam simulated by numerical simulation are compared with the destructive test data, and the results are in agreement with each other. In addition, the ultimate load-bearing capacity of each beam and the variation of longitudinal reinforcement in tensile zone with load grade under three conditions are also studied. The yield point of steel bar is determined by comparative analysis of each beam. To sum up, the analysis of nonlinearity by OpenSEES software is proved to be not only accurate, but also high maneuverability by pre-processing. It is proved that it is superior to use OpenSEES software to analyze material nonlinearity. It can provide reference value for other nonlinear analysis.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U448.217

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