發(fā)布時(shí)間：2018-05-11 03:18

  本文選題：FRP + 混凝土��； 參考：《華南理工大學(xué)》2013年碩士論文

【摘要】：纖維增強(qiáng)復(fù)合材料（Fiber Reinforced Polymer/Plastic，簡(jiǎn)稱FRP）具有優(yōu)異的物理和力學(xué)性能，其在諸多領(lǐng)域都具有廣闊的應(yīng)用前景，其中一個(gè)重要的領(lǐng)域是應(yīng)用于加固、修復(fù)老舊鋼筋混凝土結(jié)構(gòu)。由于FRP材料屬于脆性材料，將其應(yīng)用于混凝土結(jié)構(gòu)的加固工程中，還存在很多需要進(jìn)行深入研究的問題，其中比較突出的一個(gè)問題就是FRP材料與混凝土界面之間的粘結(jié)性能以及剝離破壞的研究。 FRP與混凝土界面之間的粘結(jié)性能以及剝離破壞是FRP加固混凝土結(jié)構(gòu)，乃至FRP加筋混凝土結(jié)構(gòu)技術(shù)應(yīng)用的關(guān)鍵問題，對(duì)構(gòu)件的整體性能起著決定性作用。本文針對(duì)FRP-混凝土界面在面內(nèi)剪切試驗(yàn)條件下的剝離特性進(jìn)行了系統(tǒng)的研究，提出了相應(yīng)的數(shù)值計(jì)算方法，較深入地分析并揭示了FRP-混凝土界面的剝離破壞機(jī)理。在此基礎(chǔ)之上，提出了包括能夠預(yù)測(cè)面內(nèi)剪切剝離承載力、FRP粘結(jié)長(zhǎng)度以及自動(dòng)追蹤剝離界面深度等功能的計(jì)算方法。本文的主要研究工作和創(chuàng)新性成果有： 1.基于精細(xì)有限單元法，充分考慮了混凝土單元在開裂情況下的尺寸效應(yīng)，依據(jù)Bazant提出的裂縫帶模型，提出了正確估計(jì)混凝土單元開裂軟化模量的方法。同時(shí)對(duì)混凝土單元開裂后的性能進(jìn)行了細(xì)致的分析研究，發(fā)現(xiàn)對(duì)開裂后的混凝土單元賦予一定剪切剛度有助于改善非線性有限元計(jì)算的收斂性，同時(shí)更符合實(shí)際情況。另外，本文還提出了一個(gè)全新的裂面剪力保持模型，該模型較之前的學(xué)者提出的模型，，顯得更加適用于小尺度的混凝土有限單元計(jì)算。經(jīng)計(jì)算對(duì)比，本文的模型能夠很好地計(jì)算FRP面內(nèi)剪切承載力，預(yù)測(cè)FRP有效粘結(jié)長(zhǎng)度，并且能夠自動(dòng)追蹤FRP剝離界面的深度，對(duì)界面粘結(jié)應(yīng)力的全過程變化也有較好地控制作用。其對(duì)進(jìn)一步的理論研究以及相關(guān)界面單元的開發(fā)起到指導(dǎo)性作用。 2.對(duì)精細(xì)單元法的結(jié)果進(jìn)行了深入、細(xì)致的研究，經(jīng)過大量的數(shù)值分析，提出了能夠較好地預(yù)測(cè)FRP-混凝土界面剝離的界面破壞能模型�；�于該模型，提出了全新的FRP-混凝土界面本構(gòu)模型，并編制了相應(yīng)的界面單元。將其導(dǎo)入通用有限元軟件MSC.MARC中進(jìn)行計(jì)算，計(jì)算結(jié)果與試驗(yàn)結(jié)果吻合較好。 3.基于試驗(yàn)結(jié)果、數(shù)值計(jì)算結(jié)果以及所得到的界面破壞能模型，提出了全新的FRP-混凝土界面剝離承載力計(jì)算公式以及FRP片材有效粘結(jié)長(zhǎng)度計(jì)算公式。所提出的計(jì)算公式較其他學(xué)者提出的計(jì)算公式相比，除具有更好的計(jì)算精度之外，其計(jì)算穩(wěn)定性也優(yōu)于以往的模型，且具有更加嚴(yán)密的理論依據(jù)，適合用于FRP加固混凝土結(jié)構(gòu)構(gòu)件的相關(guān)分析和設(shè)計(jì)。
[Abstract]:Fiber Reinforced Polymer-Plastics (FRP) has excellent physical and mechanical properties, and it has broad application prospects in many fields. One of the important fields is to strengthen and repair old reinforced concrete structures. Because FRP is a brittle material, there are still many problems that need to be deeply studied when it is applied to the reinforcement of concrete structure. One of the outstanding problems is the bond behavior and debonding failure between FRP material and concrete interface. The bond behavior and debonding failure between FRP and concrete interface are the key problems in the technical application of FRP strengthening concrete structures and even FRP reinforced concrete structures, and play a decisive role in the overall performance of members. In this paper, the delamination characteristics of FRP- concrete interface under in-plane shear test are systematically studied, and the corresponding numerical calculation method is put forward. The mechanism of debonding failure of FRP- concrete interface is deeply analyzed and revealed. On the basis of this, a calculation method including the function of predicting in-plane shear peeling capacity and FRP bond length and automatically tracing the depth of the delamination interface is proposed. The main research work and innovative results of this paper are as follows: 1. Based on the fine finite element method, the size effect of concrete element under crack condition is fully considered. According to the crack zone model proposed by Bazant, a method to estimate the crack softening modulus of concrete element is put forward. At the same time, the behavior of concrete element after cracking is analyzed and studied in detail. It is found that it is helpful to improve the convergence of nonlinear finite element calculation and accord with the actual situation by assigning a certain shear stiffness to the cracked concrete element. In addition, a new shear retention model for crack plane is proposed in this paper, which is more suitable for the calculation of small scale concrete finite element than that proposed by previous scholars. Through calculation and comparison, the model in this paper can well calculate the in-plane shear capacity of FRP, predict the effective bond length of FRP, and can automatically trace the depth of the FRP peel interface, which can also control the whole process of the bond stress change of the interface. It plays a guiding role in further theoretical research and the development of related interface units. 2. The results of the fine element method are studied deeply and meticulously. After a lot of numerical analysis, a model for predicting the interface failure energy of FRP- concrete interface is put forward. Based on this model, a new constitutive model of FRP- concrete interface is proposed, and the corresponding interface unit is worked out. It is introduced into the general finite element software MSC.MARC for calculation, and the calculated results are in good agreement with the experimental results. 3. Based on the experimental results, numerical results and the interface failure energy model, a new formula for calculating the peeling capacity of FRP-concrete interface and the effective bond length of FRP sheet are proposed. Compared with the formula proposed by other scholars, the proposed formula has better calculation accuracy, and its computational stability is better than that of the previous models, and it has a more rigorous theoretical basis. It is suitable for the analysis and design of concrete structural members strengthened by FRP.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU375

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