【作者】 李耀；

【导师】 李和平； 巫绪涛；

【作者基本信息】 合肥工业大学 ， 固体力学， 2009， 硕士

【摘要】 近几年来,国内外很多学者对混凝土在高压、高应变率及大变形条件下的动态响应问题作了大量的研究。随着现代数值分析技术特别是有限元分析技术及高速计算机的飞速发展,运用计算机对混凝土的冲击问题进行数值模拟分析已经得到广泛的应用。本文首先介绍了混凝土动态压缩力学性能方面的有关研究进展,并对SHPB试验技术和试验原理、以及有限元理论和数值模拟方法进行了简单的叙述。本文的重点之一是运用显式非线性动力分析软件LS-DYNA,选用Holmquist-Johnson-Cook(简称HJC)动态本构模型对混凝土SHPB试验进行了一系列的数值模拟,对HJC模型的屈服面方程、损伤机理、材料参数以及失效类型f_s进行了分析,从而对HJC动态本构模型的理论框架以及材料参数的力学特点有了一个清晰的认识。本文的另外一个重点是利用HJC模型拟合实际混凝土冲击压缩实验结果,最终得到了对C60V0系列混凝土在不同应变率作用下进行数值模拟时的HJC模型的材料参数,同时归纳出了HJC模型材料参数的确定方法,并结合实验入射波、反射波和透射波形状与数值模拟对比验证了模拟精度。更多还原

【Abstract】 In recent years, there are many domestic and abroad scholars have made a lot of study on the issues of dynamic response of concrete under the conditions of high pressures、high strain rates and large strains. With the rapid development of the modern technology , especially the finite element analysis technology and high-speed computers, the computers have been wild used to the numerical simulation analysis of the impact of concrete.First of all, the progress of the study on the dynamic compression mechanics properties of concrete are introduced briefly in the article, it also stated the problems of SHPB experiment of technology and theory and the methods of the finite element theory and the numerical simulation.One of the key points of the article is by using the explicit dynamic finite element software LS-DYNA, the numerical simulation on SHPB tests of concrete are carried out with Holmquist-Johnson-Cook(HJC)dynamic constitutive model. The HJC model of yield surface equation, the mechanism of constitutive, the material constants and the failure type f_s have been discussed. We have a clear understanding on the theoretical framework and the mechanical characteristics of the material constants of the HJC dynamic constitutive model.Another key point of the article is simulating the actual concrete model shock compression experimental results with HJC model, and by the numerical simulations on C60V0 series of concrete at different strain rates with the HJC model, to get the material constants and the determination methods of constants of HJC model. At last, the accuracy of the simulation combined with the experimental incident wave, reflected wave and transmission wave shape is verified.更多还原