基于应力应变疲劳准则的混凝土疲劳寿命分析  

Analysis of concrete fatigue life based on stress-strain fatigue criterion

作　　者：张书 马睿[1] 胡昱[1] 李庆斌[1] ZHANG Shu;MA Rui;HU Yu;LI Qingbin(State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学水圈科学与水利工程全国重点实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2024年第8期1330-1335,共6页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金重点项目(52130901)。

摘　　要：疲劳荷载作用下混凝土疲劳寿命评估对保障结构安全、实现稳定服役至关重要,应力与应变共同决定了材料疲劳破坏行为。该文根据应力应变疲劳准则约束关系,构造了描述混凝土疲劳状态的疲劳加载曲面函数。研究表明,混凝土疲劳加载曲面函数随疲劳循环次数呈现出单调递增的规律,这为建立混凝土疲劳状态的等效函数提供了条件;混凝土疲劳加载曲面函数可采用线性等效形式,而系数可通过混凝土疲劳加载过程中的特征点来标定。该文提出了MRS(maximum R-square)算法以保证等效描述结果的有效性,用等效疲劳循环次数来量化混凝土的疲劳应力应变状态,并给出了相应的评估流程和指标。该研究为混凝土的疲劳寿命分析提供了有效手段。[Objective]Accurate assessment of concrete fatigue life under fatigue load is essential to ensure the safety and stability of structures,especially the fatigue failure behavior dominated by stress and strain.The fatigue loading surface function is established to describe the fatigue state of concrete based on the constraint relationship in the stress-strain fatigue criterion.The fatigue loading surface function of concrete exhibits a monotonic variation with fatigue cycles,enabling the establishment of an equivalent function to represent the concrete fatigue state.The fatigue loading surface function of concrete can be described as a linear equivalent expression,and the coefficients can be calibrated by the characteristic points in the fatigue loading process.[Methods]Based on the constraint relationship between fatigue stress-strain and fatigue cycles,the equivalent fatigue cycles can be calculated from the fatigue stress-strain data.The equivalent fatigue cycles can effectively express the fatigue stress-strain state of the material,and the fatigue life indirectly represents the fatigue failure stress-strain state in the fatigue failure criterion of materials with the static constitutive curve as the limit value.The degree of fatigue accumulation of materials can be quantified by comparing the equivalent fatigue cycles and fatigue life.The evaluation method based on equivalent fatigue cycles overcomes the shortcomings of the current evaluation methods based on the classic fatigue criteria and fatigue envelope lines.Therefore,in this work,the fatigue loading surface function is constructed,and its evolution law is studied through the analogical form of the fatigue failure criterion of materials with a static constitutive curve as the limit value,thus proposing a description method for equivalent calibration and solving the equivalent fatigue cycles.The fatigue loading surface function is proposed to describe the fatigue state and determine the constraint relationship between fatigue stress and strain and fatigue

关 键 词：疲劳应力 疲劳应变 等效求解 状态评估 疲劳循环次数 

分 类 号：TV1[水利工程]