基于疲劳应变演化的混凝土弯曲强度退化分析
发布时间：2018-11-27 13:19
【摘要】：为了研究混凝土在弯曲疲劳荷载作用下的强度退化规律,提出了基于疲劳应变演化的混凝土弯曲强度退化分析方法。基于疲劳应变三阶段演化规律及目前拟合方法的不足,构造了水平S形非线性应变演化模型,讨论了模型参数的物理含义、取值范围以及参数对模型曲线的影响;通过对常用损伤变量优缺点的分析,在应变空间上建立了疲劳损伤演化方程;结合混凝土疲劳强度退化的边界条件与同一损伤状态疲劳应变与弯曲强度必然存在唯一对应关系假定,建立了混凝土弯曲强度衰减方程式,整个过程都用玻璃纤维混凝土的试验数据进行了对比分析与验证。研究结果表明:水平S形非线性应变演化模型涵盖了疲劳应变演化规律的各种类型,具有适应性强、精度高的特点,适用于玻璃纤维混凝土疲劳应变演化的描述,也可在钢纤维混凝土以及各种再生混凝土疲劳应变分析中推广应用;基于疲劳应变演化模型建立的损伤演化曲线起初增长较快,中间线性增大,循环比超过0.9时急速增加,具有从左下角至右上角的水平S形变化规律,且与试验曲线吻合较好;弯曲强度衰减曲线起初下降较快,中间线性变化,循环比超过0.9时又迅速下降,衰减曲线为从左上角至右下角的S形曲线。
[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.
【作者单位】： 重庆交通大学山区桥梁与隧道工程国家重点实验室培育基地;重庆三峡学院土木工程学院;
【基金】：国家杰出青年科学基金项目(5142500405) 国家自然科学基金项目(51508058) 山区桥梁与隧道工程国家重点实验室培育基地项目(CQSLBF-Y16-6) 重庆市教委科学技术研究项目(KJ1710237)
【分类号】：U441.4
，
本文编号：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.
【作者单位】： 重庆交通大学山区桥梁与隧道工程国家重点实验室培育基地;重庆三峡学院土木工程学院;
【基金】：国家杰出青年科学基金项目(5142500405) 国家自然科学基金项目(51508058) 山区桥梁与隧道工程国家重点实验室培育基地项目(CQSLBF-Y16-6) 重庆市教委科学技术研究项目(KJ1710237)
【分类号】：U441.4
，
本文编号：2360927
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