CAJ | 학술논문

混凝土动态力学行为具有明显的率相关性，探讨了加载速率及其突变对混凝土压缩破坏模式及宏观力学性能的影响。考虑混凝土细观结构非均质性的影响，从细观角度出发将混凝土看作由骨料、砂浆基质及过渡区界面组成的三相复合材料。采用耦合应变率效应的塑性损伤本构关系模型来描述砂浆基质及界面的动态力学行为；认为骨料不产生断裂破坏，为弹性体。采用Monte Carlo法建立了混凝土二维随机骨料模型，首先对Dilger等混凝土动态压缩试验进行数值模拟，数值与试验结果的良好吻合证明了方法的可行性及细观参数选取的准确性。进而探讨了细观组分应变率效应的影响，对比了混凝土非均质模型与宏观均匀模型的应变率效应，最后分析了软化阶段加载速率突变对混凝土破坏模式及宏观应力应变关系的影响，并得到了一些有益结论。
혼응토동태역학행위구유명현적솔상관성，탐토료가재속솔급기돌변대혼응토압축파배모식급굉관역학성능적영향。고필혼응토세관결구비균질성적영향，종세관각도출발장혼응토간작유골료、사장기질급과도구계면조성적삼상복합재료。채용우합응변솔효응적소성손상본구관계모형래묘술사장기질급계면적동태역학행위；인위골료불산생단렬파배，위탄성체。채용Monte Carlo법건립료혼응토이유수궤골료모형，수선대Dilger등혼응토동태압축시험진행수치모의，수치여시험결과적량호문합증명료방법적가행성급세관삼수선취적준학성。진이탐토료세관조분응변솔효응적영향，대비료혼응토비균질모형여굉관균균모형적응변솔효응，최후분석료연화계단가재속솔돌변대혼응토파배모식급굉관응력응변관계적영향，병득도료일사유익결론。
The dynamic behavior of concrete has obvious strain-rate dependency.Here,the effects of loading rate and its sudden change on concrete compressive failure pattern and its macroscopic dynamic properties were studied. Considering the influence of concrete heterogeneity,from view point of meso-scale,concrete is treated as a three-phase composite composed of aggregate,mortar matrix and interfacial transition zone (ITZ ) between them.The damaged plasticity theory combined with strain rate effect was used to describe the dynamic properties of mortar matrix and ITZ.It was assumed that aggregate phase does not damage,and thus aggregate is set to be elastic.A planar concrete random aggregate structure was established with Monte Carlo method.The dynamic compressive tests conducted by Dilger et al were simulated at first,and the good agreement between the presented numerical results and the experimental data indicated the feasibility of the presented meso-scopic approach and the reusonableness of the selected meso-scale parameters.Subsequently,the material strain-rate effect was discussed,and the strain-rate effects of a concrete meso-scale heterogeneous model and a concrete macro-scale homogeneous model were compared and studied.Finally,the influence of the sudden change of loading rate during the softening stage on concrete failure mode and macroscopic mechanical properties of concrete was analyzed.Some useful conclusions were obtained.