本文選題：預(yù)應(yīng)力 + CFRP片材��； 參考：《長(zhǎng)沙理工大學(xué)》2015年碩士論文

【摘要】：研究表明由于CFRP片材與混凝土、鋼筋的熱膨脹系數(shù)存在差異,當(dāng)環(huán)境溫度發(fā)生變化時(shí)在加固結(jié)構(gòu)的粘結(jié)界面將不可避免地產(chǎn)生溫度應(yīng)力。而針對(duì)在溫度變化條件下不同厚度的粘結(jié)膠層和不同大小的初始應(yīng)力對(duì)預(yù)應(yīng)力CFRP片材加固混凝土梁界面溫度應(yīng)力影響的研究較少。本試驗(yàn)對(duì)粘結(jié)膠層厚度為2mm、4mm、6mm和初始應(yīng)力為CFRP片材抗拉強(qiáng)度的10%、20%、30%的試驗(yàn)梁進(jìn)行溫度試驗(yàn),通過(guò)對(duì)試驗(yàn)所測(cè)數(shù)據(jù)進(jìn)行數(shù)值擬合與分析,同時(shí)結(jié)合理想粘結(jié)狀態(tài)下對(duì)加固試驗(yàn)梁的微元段的理論受力分析,尋求在溫度變化作用下構(gòu)件的界面溫度應(yīng)力的分布規(guī)律以及粘結(jié)膠層的厚度、初始應(yīng)力大小對(duì)加固結(jié)構(gòu)界面溫度應(yīng)力的影響。研究結(jié)果表明:1.對(duì)于不同的初始應(yīng)力,相同粘結(jié)膠層厚度的試驗(yàn)梁,初始應(yīng)力越大,試驗(yàn)梁的CFRP片材的應(yīng)變沿梁分布的數(shù)值越大。而對(duì)于不同厚度的粘結(jié)膠層,相同初始應(yīng)力的試驗(yàn)梁,粘結(jié)膠層厚度越大,應(yīng)變沿梁分布的數(shù)值越小。同時(shí)對(duì)于厚度為2mm、4mm的粘結(jié)膠層的試驗(yàn)梁,其初始應(yīng)力越大,試驗(yàn)梁的CFRP片材的應(yīng)變發(fā)生急劇變化的區(qū)域越大。而膠層厚度為6mm的試驗(yàn)梁CFRP片材應(yīng)變沿梁變化相對(duì)穩(wěn)定,并無(wú)應(yīng)變急劇變化區(qū)域。其應(yīng)變變化速率也基本保持不變。2.通過(guò)數(shù)值擬合得到了梁端的預(yù)應(yīng)力CFRP片材應(yīng)變與溫度變化關(guān)系式。關(guān)系曲線表明,在相同粘結(jié)膠層厚度的條件下,初始應(yīng)力越小,試驗(yàn)梁梁端CFRP片材應(yīng)變數(shù)值越小,應(yīng)變變化速率發(fā)生改變時(shí)對(duì)應(yīng)的溫度則越高。在相同初始應(yīng)力的條件下,粘結(jié)膠層厚度為4mm的試驗(yàn)梁端CFRP片材的應(yīng)變變化速率發(fā)生改變時(shí)所對(duì)應(yīng)的溫度最高。3.由試驗(yàn)結(jié)果與理論分析結(jié)果可知,同一初始應(yīng)力條件下,粘結(jié)膠層的厚度越小,試驗(yàn)梁的錨固端與跨中處的最大界面溫度應(yīng)力越大。同一厚度的粘結(jié)膠層的條件下,初始預(yù)應(yīng)力越大的試驗(yàn)梁錨固端與跨中處所對(duì)應(yīng)的最大界面溫度應(yīng)力也越大。因而采用相同的粘結(jié)膠層厚度時(shí),建議使用0.1P的初始應(yīng)力來(lái)開展預(yù)應(yīng)力CFRP片材對(duì)結(jié)構(gòu)的加固。4.在同一初始應(yīng)力條件下,當(dāng)溫度在0℃~20℃范圍內(nèi)變化時(shí),粘結(jié)膠層厚度為4mm的試驗(yàn)梁的界面溫度應(yīng)力最小;當(dāng)溫度變化在20℃~47℃范圍內(nèi)變化時(shí),粘結(jié)膠層厚度為6mm的試驗(yàn)梁的界面溫度應(yīng)力最小。建議在溫度較低的寒冷采用4mm的粘結(jié)膠層進(jìn)行預(yù)應(yīng)力CFRP片材加固結(jié)構(gòu)。而在溫度相對(duì)高的地區(qū)采用6mm的粘結(jié)膠層進(jìn)行結(jié)構(gòu)的加固更合適。
[Abstract]:The results show that the thermal expansion coefficient of steel bar is different between CFRP sheet and concrete. When the ambient temperature changes, the thermal stress will inevitably occur at the bond interface of the strengthened structure. However, there is little research on the effect of different thickness adhesive layer and different initial stress on the interface temperature stress of prestressed CFRP sheet reinforced concrete beam under the condition of temperature change. In this experiment, the temperature of the test beam with the thickness of 2 mm and 4 mm / 6 mm and the tensile strength of CFRP sheet with the initial stress of 10% and 20% was tested, and the experimental data were fitted and analyzed numerically. At the same time, combining with the theoretical analysis of the micro-element section of the strengthened test beam under the ideal bond state, the distribution law of the interfacial temperature stress and the thickness of the adhesive layer are sought under the influence of the temperature change. The effect of the initial stress on the temperature stress at the interface of the strengthened structure. The results of the study show that 1: 1. For different initial stress, the larger the initial stress is, the larger the strain distribution of CFRP sheet is along the beam. For different thickness of adhesive layer, the larger the thickness of adhesive layer, the smaller the value of strain distribution along the beam with the same initial stress. At the same time, the larger the initial stress, the larger the area where the strain of CFRP sheet material changes sharply for the test beam with a thickness of 2 mm or 4 mm. However, the strain of CFRP-sheet with thickness of 6mm is relatively stable along the beam, and there is no sharp change region of strain. The strain change rate also remained unchanged basically. 2. The relationship between strain and temperature of prestressed CFRP sheet at beam end is obtained by numerical fitting. The relationship curve shows that the smaller the initial stress is, the smaller the strain value of CFRP sheet at the end of beam is, and the higher the temperature is when the strain rate changes. Under the same initial stress condition, the maximum temperature corresponding to the change of strain rate at the end of the beam when the thickness of the adhesive layer is 4mm is changed. 3. From the experimental results and theoretical analysis results, it can be seen that under the same initial stress condition, the larger the thickness of adhesive layer is, the greater the maximum interfacial temperature stress between the anchoring end and the middle span of the test beam is. Under the condition of the same thickness of adhesive layer, the maximum interfacial temperature stress corresponding to the Anchorage end and the middle of the span of the test beam with larger initial prestress is also greater. Therefore, when the thickness of adhesive layer is the same, it is suggested that the initial stress of 0.1P should be used to strengthen the structure with prestressed CFRP sheet. Under the same initial stress condition, when the temperature varies from 0 鈩，

本文編號(hào)：2040263