【摘要】：為了研究混凝土在彎曲疲勞荷載作用下的強(qiáng)度退化規(guī)律,提出了基于疲勞應(yīng)變演化的混凝土彎曲強(qiáng)度退化分析方法�；谄趹�(yīng)變?nèi)A段演化規(guī)律及目前擬合方法的不足,構(gòu)造了水平S形非線性應(yīng)變演化模型,討論了模型參數(shù)的物理含義、取值范圍以及參數(shù)對(duì)模型曲線的影響;通過對(duì)常用損傷變量?jī)?yōu)缺點(diǎn)的分析,在應(yīng)變空間上建立了疲勞損傷演化方程;結(jié)合混凝土疲勞強(qiáng)度退化的邊界條件與同一損傷狀態(tài)疲勞應(yīng)變與彎曲強(qiáng)度必然存在唯一對(duì)應(yīng)關(guān)系假定,建立了混凝土彎曲強(qiáng)度衰減方程式,整個(gè)過程都用玻璃纖維混凝土的試驗(yàn)數(shù)據(jù)進(jìn)行了對(duì)比分析與驗(yàn)證。研究結(jié)果表明:水平S形非線性應(yīng)變演化模型涵蓋了疲勞應(yīng)變演化規(guī)律的各種類型,具有適應(yīng)性強(qiáng)、精度高的特點(diǎn),適用于玻璃纖維混凝土疲勞應(yīng)變演化的描述,也可在鋼纖維混凝土以及各種再生混凝土疲勞應(yīng)變分析中推廣應(yīng)用;基于疲勞應(yīng)變演化模型建立的損傷演化曲線起初增長(zhǎng)較快,中間線性增大,循環(huán)比超過0.9時(shí)急速增加,具有從左下角至右上角的水平S形變化規(guī)律,且與試驗(yàn)曲線吻合較好;彎曲強(qiáng)度衰減曲線起初下降較快,中間線性變化,循環(huán)比超過0.9時(shí)又迅速下降,衰減曲線為從左上角至右下角的S形曲線。
[Abstract]:In order to study the law of strength degradation of concrete under bending fatigue load, a method of bending strength degradation analysis based on fatigue strain evolution is proposed. Based on the three-stage evolution law of fatigue strain and the deficiency of the current fitting method, a horizontal S-shape nonlinear strain evolution model is constructed. The physical meaning of model parameters, the range of values and the influence of parameters on the model curve are discussed. By analyzing the advantages and disadvantages of common damage variables, the fatigue damage evolution equation is established in strain space. Based on the assumption that the boundary condition of fatigue strength degradation of concrete must have a unique corresponding relationship with the fatigue strain and bending strength in the same damage state, the bending strength attenuation equation of concrete is established. The whole process is compared and verified with the test data of fiberglass concrete. The results show that the horizontal S-shape nonlinear strain evolution model covers various types of fatigue strain evolution law and has the characteristics of strong adaptability and high precision. It is suitable for describing the fatigue strain evolution of glass fiber reinforced concrete. It can also be used in fatigue strain analysis of steel fiber concrete and recycled concrete. The damage evolution curve based on the fatigue strain evolution model increases rapidly at first, increases linearly in the middle, increases rapidly when the cycle ratio exceeds 0.9, and has the horizontal S-shape variation law from the lower left corner to the upper right corner. And the curve is in good agreement with the test curve. The attenuation curve of bending strength decreases rapidly at first and changes linearly in the middle. When the cycle ratio exceeds 0.9, the attenuation curve is a S-shaped curve from the upper left corner to the lower right corner.
【作者單位】： 重慶交通大學(xué)山區(qū)橋梁與隧道工程國(guó)家重點(diǎn)實(shí)驗(yàn)室培育基地;重慶三峽學(xué)院土木工程學(xué)院;
【基金】：國(guó)家杰出青年科學(xué)基金項(xiàng)目(5142500405) 國(guó)家自然科學(xué)基金項(xiàng)目(51508058) 山區(qū)橋梁與隧道工程國(guó)家重點(diǎn)實(shí)驗(yàn)室培育基地項(xiàng)目(CQSLBF-Y16-6) 重慶市教委科學(xué)技術(shù)研究項(xiàng)目(KJ1710237)
【分類號(hào)】：U441.4
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本文編號(hào)：2360927