混凝土徐变柔度函数的高效逼近方法  

Efficient Approximation Method for Concrete Creep Compliance Function

作　　者：向华伟 荣华[1,2,3] 范兴朗 耿岩 白林洪 XIANG Huawei;RONG Hua;FAN Xinglang;GENG Yan;BAI Linhong(Central Research Institute of Building and Construction Co.,Ltd.,MCC Group,Beijing 100088,China;Inspection and Certification Co.,Ltd.,MCC Group,Beijing 100088,China;Central Research Institute of Building and Construction Co.,Ltd.(Shenzhen),MCC Group,Shenzhen 518066,China;Zhejiang University of Technology,Hangzhou 310023,China)

机构地区：[1]中冶建筑研究总院有限公司,北京100088 [2]中冶检测认证有限公司,北京100088 [3]中冶建筑研究总院(深圳)有限公司,广东深圳518066 [4]浙江工业大学,浙江杭州310023

出　　处：《原子能科学技术》2024年第8期1689-1696,共8页Atomic Energy Science and Technology

基　　金：国家重点研发计划(2019YBF1900903);中国博士后科学基金(2023M734085);北京市科技新星计划(Z201100006820045)。

摘　　要：混凝土徐变是引起安全壳预应力损失的主要因素之一,采用指数算法求解混凝土徐变效应时需要将混凝土徐变柔度函数采用Dirichlet级数表达,如何获得精确表征柔度函数的Dirichlet级数是实现指数算法的关键。基于连续延迟谱法,本文提出一种求解拉普拉斯逆变换的Weeks方法来逼近Dirichlet级数。对工程中常用的CEB MC90徐变模型,构建了基于Weeks方法的Dirichlet级数逼近算法,并给出了提高方法效率的相关参数取值范围。结果表明,提出的方法仅需对原混凝土徐变柔度函数求1阶导数,即可返回时域函数的显示表达式,避免了高阶求导存在计算复杂和计算效率低的问题。将本文方法计算结果与原柔度函数解析解进行对比,验证了方法的有效性。For concrete,the strain tends to grow when the stress is kept at a constant level.This phenomenon is usually referred to as creep.Creep is an important physical property of concrete.For a prestressed concrete containment,creep could lead to prestress losses,stress redistribution,additional displacements,and even cracking.In general,the stress-strain relation of creep is nonlinear,but the principal stresses of concrete remain within the service stress range which is below 40%to 50%of the uniaxial strength.Therefore,the superposition principle can be utilized in linear elasticity,which works with the current values of stress and strain.Based on the theory of linear viscoelasticity,the principle of superposition can be used to characterize creep at a constant stress and the compliance function is used to describe the concrete creep mathematically,which facilitates numerical calculations.However,when the exponential algorithm is used to solve the creep effect of concrete,it is necessary to express the concrete creep compliance function by Dirichlet series and the calculation of the Dirichlet series corresponding to the compliance function is the key to implementing the exponential algorithm.The Weeks method for the inverse Laplace transform was used to approximate the Dirichlet series based on the continuous retardation spectrum method.The problem of approximating the concrete creep compliance function by the Weeks method was examined.First,the process of using the Weeks method to solve the continuous retardation spectrum was introduced.By taking the CEB MC90 creep model commonly used in engineering as an example,the equations for solving the concrete creep compliance function were derived by the Weeks method.The idea for improving the performance of the Weeks method was proposed.Based on this idea,the ranges of the various parameters that play a role in this solution were proposed.The numerical integration formula for the time-dependent term in the compliance function was derived.The results show that the calculatio

关 键 词：混凝土安全壳 混凝土徐变 柔度函数 DIRICHLET级数 连续延迟谱 Weeks方法 

分 类 号：TL99[核科学技术—核技术及应用] TU378[建筑科学—结构工程]