基于切口梁弯曲响应的UHPC受拉性能反演分析  

INVERSE ANALYSIS FOR DETERMINING THE TENSILE PROPERTIES OF UHPC BASED ON BENDING RESPONSE OF NOTCHED BEAMS

作　　者：郭义庆 王俊颜[1] GUO Yi-qing;WANG Jun-yan(Key Laboratory of Advanced Civil Engineering Materials,Ministry of Education,Tongji University,Shanghai 201804,China;Department of Structural Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学先进土木工程材料教育部重点实验室,上海201804 [2]同济大学建筑工程系,上海200092

出　　处：《工程力学》2024年第4期151-160,共10页Engineering Mechanics

基　　金：国家自然科学基金项目(52108239);宁波市重大科技专项项目(2020Z034);福建省交通运输科技项目(202125)。

摘　　要：为了更加快速、准确地获取超高性能混凝土(UHPC)材料的拉伸性能,该文基于切口梁四点弯曲试验获得的荷载-切口张开位移(CMOD)响应,提出了一种UHPC拉伸性能简化反演分析方法。该方法采用了考虑裂纹局部化的非线性铰模型和可描述拉伸应变硬化或应变软化特征的多折线UHPC受拉应力-应变关系。通过5种钢纤维掺量的UHPC切口梁弯曲试验和轴拉试验的验证以及模型参数分析表明:在切口梁弯曲响应的离散性较低时,提出的计算模型能够准确地预测应变硬化和应变软化UHPC的受拉初裂强度和极限强度;随弯曲响应的离散性增大,轴拉应力的预测值与实测值的偏差越大;特征长度及特征点数量对应变软化UHPC受拉应力-缝宽曲线预测结果的影响较小,但对于应变硬化UHPC,特征长度的增大和特征点的减少都会导致其极限强度预测值偏高。通过应用表明:采用基于荷载-CMOD响应的非线性铰模型预测UHPC的受拉性能具有较好的可行性。In order to efficiently obtain the tensile properties of ultra-high performance concrete(UHPC),a simplified inverse analysis method is proposed based on load-crack mouth open displacement(CMOD)response obtained from the notched bending test.The method consists of a hinge model,which takes into account the influence of the crack localization,and a segmented stress-strain relationship,which is capable of describing the tensile strain softening and strain hardening behaviors.The proposed model can accurately predict the first cracking tensile strength and ultimate tensile strength of strain hardening and strain softening UHPC,as validated by the comparison between the predicted results and uniaxial tensile test results.The predicted results are higher than the test results with the increasing discreteness of the bending response.The model parameter analysis indicated that the predicted tensile properties of strain softening UHPC are slightly affected by the reference length and characteristic point number,while the overestimation of predicted ultimate strength was increased with a larger reference length and fewer characteristic points for strain hardening UHPC.The model can be implemented for inverse analysis of the tensile stress-crack width curve.

关 键 词：超高性能混凝土 拉伸性能 切口梁四点弯 非线性铰模型 反演分析 

分 类 号：TU528.572[建筑科学—建筑技术科学]