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Constitutive Law of Concrete in early ages Including Semi-fluid State and Analysis on Initial Crack Problem after Casting

包括半流态在内的早期混凝土本构规律及浇注后初期裂缝问题分析

基本信息

批准号：
13650506
负责人：
TANABE Tada-aki
金额：
$ 2.11万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

In this year, constitutive law of concrete in transient state has been developed and application software to numerical problem has been tried to be created. Especially, following two targets are focused.One is to express fluidity of transient concrete mathematically. For the purpose of practical use, stress-strain relationship of fluid media is thought to be express in three dimensional tangential form including adequate homogeneous creep law. This is because even fluid media such as transient concrete has small but nonzero shear resistance. Moreover, numerical expression of plastic behavior except time dependent part is given by not classical plastic theorem but evaluating Lattice Equivalent Continuum Method (LECM) in order to have better numerical convergence of force equilibrium and to reduce computation time.The other is to present rigorous constitutive model in terms of both plastic theorem and various experiments.The aforementioned targets are almost completed. Finally, numerical analysis of transient concrete structure subjected to bleeding shrinkage is carried to reveal characteristics of software and it is found that the software can not only express strain localization induced by bleeding shrinkage more evidently but also have better numerical convergence of solution compared with the software based on conventional plastic theorem.However, as numerical discussion for initial stress problem is insufficient, much more numerical analysis of initial stress problem under various conditions should be carried and discussed.

今年，开发了混凝土瞬态本构关系，并尝试创建数值问题应用软件。本文主要研究了以下两个方面的问题：一是用数学的方法来表达非稳定混凝土的流动性;为了便于实际应用，认为流体介质的应力-应变关系可以用三维切向形式表示，其中包含适当的均匀蠕变规律。这是因为即使是流体介质，如瞬态混凝土，也具有较小但非零的剪切阻力。此外，为了使力平衡的数值收敛性更好，减少计算时间，除与时间有关的部分外，塑性行为的数值表达式不是用经典塑性理论给出的，而是用评价格点等效连续法（LECM）给出的，二是根据塑性理论和各种实验给出严格的本构模型，上述目标基本完成。最后，对混凝土结构在收缩作用下的瞬态过程进行了数值分析，揭示了该软件的特点，发现与基于常规塑性理论的软件相比，该软件不仅能更明显地表达收缩引起的应变局部化，而且具有更好的数值收敛性，但由于对初始应力问题的数值讨论不够充分，各种条件下初应力问题的数值分析还有待进一步的探讨。