基于疲勞應變演化的混凝土彎曲強度退化分析
發(fā)布時間：2018-11-27 13:19
【摘要】：為了研究混凝土在彎曲疲勞荷載作用下的強度退化規(guī)律,提出了基于疲勞應變演化的混凝土彎曲強度退化分析方法�；谄趹�?nèi)A段演化規(guī)律及目前擬合方法的不足,構造了水平S形非線性應變演化模型,討論了模型參數(shù)的物理含義、取值范圍以及參數(shù)對模型曲線的影響;通過對常用損傷變量優(yōu)缺點的分析,在應變空間上建立了疲勞損傷演化方程;結合混凝土疲勞強度退化的邊界條件與同一損傷狀態(tài)疲勞應變與彎曲強度必然存在唯一對應關系假定,建立了混凝土彎曲強度衰減方程式,整個過程都用玻璃纖維混凝土的試驗數(shù)據(jù)進行了對比分析與驗證。研究結果表明:水平S形非線性應變演化模型涵蓋了疲勞應變演化規(guī)律的各種類型,具有適應性強、精度高的特點,適用于玻璃纖維混凝土疲勞應變演化的描述,也可在鋼纖維混凝土以及各種再生混凝土疲勞應變分析中推廣應用;基于疲勞應變演化模型建立的損傷演化曲線起初增長較快,中間線性增大,循環(huán)比超過0.9時急速增加,具有從左下角至右上角的水平S形變化規(guī)律,且與試驗曲線吻合較好;彎曲強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】： 重慶交通大學山區(qū)橋梁與隧道工程國家重點實驗室培育基地;重慶三峽學院土木工程學院;
【基金】：國家杰出青年科學基金項目(5142500405) 國家自然科學基金項目(51508058) 山區(qū)橋梁與隧道工程國家重點實驗室培育基地項目(CQSLBF-Y16-6) 重慶市教委科學技術研究項目(KJ1710237)
【分類號】：U441.4
，
本文編號：2360927
[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】： 重慶交通大學山區(qū)橋梁與隧道工程國家重點實驗室培育基地;重慶三峽學院土木工程學院;
【基金】：國家杰出青年科學基金項目(5142500405) 國家自然科學基金項目(51508058) 山區(qū)橋梁與隧道工程國家重點實驗室培育基地項目(CQSLBF-Y16-6) 重慶市教委科學技術研究項目(KJ1710237)
【分類號】：U441.4
，
本文編號：2360927
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