基于黏弹特性的沥青损伤演化规律分析

发布时间：2018-05-14 11:27

本文选题：沥青 + 多阶段疲劳试验　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：沥青损伤演化规律是指能准确描述荷载作用下沥青内部结构损伤程度的损伤变量的变化规律,多年来,研究者们一直密切关注沥青损伤演化规律的研究,且提出了多种损伤演化函数。但现有的损伤演化函数在内部结构损伤状态描述方面难以体现黏弹特性,未剔除触变性的影响。虽然目前大多数研究以模量和能量的变化以及一些特殊函数(如Weibull函数等)作为损伤演化函数,但结果并不理想。黏弹本构模型作为沥青核心黏弹特性,从该模型理论角度出发,通过分析以表征内部结构损伤状态改变的黏弹模型参数作为损伤变量,从沥青内部微观结构的变化分析沥青的损伤的方法,为沥青损伤演化规律分析提供新的研究思路。鉴于此,从沥青的损伤特性入手,首先基于常规损伤试验测试动、静载下沥青损伤特性,分析了不同温度、不同沥青下动载下沥青复数模量、相位角、耗散能等动态黏弹参数与静载下沥青蠕变柔量、应变、黏度等黏弹参数随荷载作用次数/时间的变化规律。研究表明,沥青疲劳过程中,沥青宏观黏弹参数复数模量、耗散能、累积耗散能随荷载作用次数增加均呈现两阶段的变化趋势,相位角呈现三阶段的变化趋势。在不考虑设备因素,沥青蠕变损伤过程中,蠕变柔量-时间曲线、应变-时间曲线、黏度-时间曲线均呈现两阶段的变化趋势。同时设计并验证了多阶段疲劳试验/多阶段蠕变试验,为获取沥青内部结构黏弹模型特征参数奠定基础。其次,基于多阶段疲劳试验/多阶段蠕变试验分析沥青损伤过程中内部结构黏弹参数主曲线簇损伤演化规律,在此基础上结合CAM模型进行沥青内部结构状态随损伤变化的初步分析。研究发现,荷载作用初期,沥青内部结构黏弹参数主曲线基本重合,随着荷载作用时间增加沥青复数模量-频率主曲线向纵坐标轴反方向平行移动,且其间距不断增大,相位角-频率主曲线在反方向移动时,后期高频范围内相位角也不断降低。复数模量-相位角主曲线簇在不断向纵坐标轴反方向移动的同时,且其弧线状主曲线呈现曲线两端先缩短后增长的趋势;弧线状损耗模量-储存模量主曲线簇呈现弧度与弧长度不断缩短的变化趋势。沥青疲劳/蠕变损伤过程中,CAM模型参数G*g、fc、fd、Rd、md基本保持恒定,表征沥青内部结构松弛时间谱宽度的模型参数R(k,me) 随荷载作用时间增加均呈现前期基本恒定、后期由快及慢不断增大的变化趋势。最后,基于经典本构模型广义Kelvin-Voigt模型与分数阶导数模型1S2P1D,分析了多个表征沥青内部结构状态的模型特征参数的变化规律。基于此,选取对损伤敏感性高的模型参数作为沥青损伤变量,并基于沥青损伤变量阐述了沥青损伤演化规律。研究发现,表征沥青核心黏弹性质的CAM模型参数R值、广义Kelvin-Voigt模型参数松弛模量E2、E3、E4模型特征参数具有明显的变化规律,结合均匀分布的均方差值分析,本研究选取参数E2+E3/2作为沥青疲劳/蠕变损伤变量。沥青疲劳损伤过程中,沥青松弛模量E2+E3/2呈现两个明显的变化阶段。第一阶段松弛模量E2+E3/2参数基本保持恒定,这从内部结构稳定状态的角度剔除了疲劳荷载作用前期触变性的影响;疲劳第二阶段松弛模量E2+E3/2参数基本呈现初期线性减小、后期由快及慢不断减小的变化趋势,经验证其受界面裂纹扩展机制所影响。沥青蠕变损伤过程中,沥青松弛模量E2+E3/2呈现两个明显的变化阶段。蠕变第一阶段松弛模量E2+E3/2缓慢线性下降;蠕变第二阶段,松弛模量E2+E3/2参数呈现迅速线性减小的变化趋势。论文阐述了沥青损伤过程中内部结构黏弹参数主曲线簇与表征内部结构状态模型特征参数的变化过程,为沥青损伤演化规律的提出与力学性能的预测提供了理论依据,同时也为其他黏弹性材料损伤演化研究提供一定的参考与依据。
[Abstract]:The evolution law of asphalt damage refers to the change law of damage variable which can accurately describe the damage degree of asphalt internal structure under load. For many years, researchers have been paying close attention to the research of the evolution law of asphalt damage, and many damage evolution functions have been put forward. But the existing damage evolution function is described in the internal structure damage state. It is difficult to reflect the viscoelastic properties and do not eliminate the effect of thixotropy. Although most of the current studies take the changes of modulus and energy and some special functions (such as Weibull function, etc.) as damage evolution functions, the results are not ideal. The viscoelastic constitutive model, as a core viscoelastic characteristic of asphalt, is analyzed from the theoretical point of view of the model. The parameter of the viscoelastic model that characterizing the change of the internal structure damage state is used as the damage variable, the method of asphalt damage analysis is analyzed from the change of the internal microstructure of the asphalt, which provides a new research idea for the analysis of the asphalt damage evolution law. The dynamic viscoelastic modulus, phase angle, dissipative energy and other dynamic viscoelastic parameters, such as creep flexibility, strain and viscosity under static load, are analyzed. The study shows that the modulus of complex modulus of asphalt macro viscoelastic parameters is dissipated in the process of asphalt fatigue. The cumulative dissipative energy shows a two stage change trend with the increase of load times, and the phase angle presents a trend of change in the three stage. In the process of asphalt creep damage, the creep flexibility time curve, strain time curve and viscosity time curve have two stages of change in the process of asphalt creep damage. The stage fatigue test / multi-stage creep test lays the foundation for obtaining the characteristic parameters of the internal structural viscoelastic model of asphalt. Secondly, based on the multi-stage fatigue test / multi-stage creep test, the damage evolution of the main viscoelastic parameters of the internal structure of the internal structure in the process of asphalt damage is analyzed. On this basis, the internal structure of asphalt is carried out in combination with the CAM model. The initial analysis of the change of state with the damage shows that the main curve of the viscoelastic parameters of the internal structure of asphalt is basically coincided with the loading time. With the increasing of loading time, the main curve of the modulus of asphalt is moving parallel to the reverse direction of the longitudinal axis, and its distance is increasing, and the phase angle frequency main curve moves in the reverse direction, and then the phase angle frequency main curve moves in the reverse direction. The phase angle in the period of high frequency is also decreasing. The complex modulus phase angle principal curve cluster is moving in the reverse direction to the longitudinal axis, and its arc shape main curve shows the trend of shortening and then increasing at both ends of the curve; the arc like loss modulus - the main curve of the storage modulus presents the changing trend of the arc and the arc length. During the process of green fatigue / creep damage, the parameters of CAM model G*g, FC, FD, Rd, MD are basically constant. The model parameter R (k, me) representing the width of the relaxation time spectrum of the internal structure of asphalt, R (k, me), with the increase of load time, is basically constant in the early stage, and in the later period it is constantly increasing from fast and slow. Finally, based on the classical constitutive model generalized Kelvin-Voigt. The model and the fractional derivative model 1S2P1D are used to analyze the variation of the model characteristic parameters which represent the internal structure state of the asphalt. Based on this, the model parameters with high damage sensitivity are selected as the asphalt damage variables, and the asphalt damage modeling is expounded based on the asphalt damage variable. The research shows that the asphalt core viscoelasticity is characterized. The parameter R value of the qualitative CAM model, the parameter relaxation modulus of the generalized Kelvin-Voigt model E2, the E3 and E4 model have obvious change law. Combining the homogeneous distribution of the mean square difference analysis, the parameter E2+E3/2 is selected as the asphalt fatigue / creep damage variable. The asphalt relaxation modulus E2+E3/2 presents two obvious in the process of asphalt fatigue damage. The first phase of the relaxation modulus E2+E3/2 parameter is basically constant, which excludes the effect of the early thixotropy of the fatigue load from the angle of the internal structural stability; the second phase relaxation modulus E2+E3/2 parameter of the fatigue is basically linear decreasing in the initial stage, and the change trend from the fast and slow decreasing in the later period is proved to be subject to the fatigue modulus. In the process of asphalt creep damage, the asphalt relaxation modulus E2+E3/2 presents two obvious changes during the creep damage process. The first stage of the creep modulus E2+E3/2 slows down slowly, the second stage of creep, the E2+E3/2 parameter of the relaxation modulus presents a rapid linear decreasing trend. The paper describes the asphalt damage process. The change process of the internal structural viscoelastic parameter main curve cluster and the characteristic parameter of the internal structure state model provides the theoretical basis for the asphalt damage evolution law and the prediction of the mechanical properties. At the same time, it also provides some reference and basis for the damage evolution of other viscoelastic materials.

【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U414

【参考文献】