Numerical Analysis Of The Elastioplastic Damage Response For Concrete Under Dynamic Loading

With the rapid economic development of China, we have become a real super country Political arena has become increasingly important, although under the current structure the theme of peaceful is under development. However, in some areas of other countries or small scale ignition occurs from time to time. In order to protect the lives and property of ordinary people, the systematic study of building structures on impact is particularly important now. And currently civil construction of reinforced concrete is still the main structural material, to carry out concrete structure under impact loading in the high-speed response of the structure of better understanding of the mechanical properties of concrete, making the maximum decrease the damage caused by the unknown hazards of great significance.Currently, the performance of concrete materials at home and abroad to carry out research is in full swing, test methods and numerical simulation methods go hand in hand, has made encouraging progress one after another, the difference constitutes the concrete itself, not the concrete material properties controlled by many factors. But with the current rapid development of computer technology, computational simulation tools to make good use of resources more rational, scientific and technological development as the current study under the best of these problems. The emphases of this thesis are focused on three aspects of the subject..(1) To take into account of the concrete under impact loading at high plastic damage and the complexity of damage propagation. The paper based on Ragueneau and Burlion's basis work, developed Gurson-Tvergaard-Needleman constitutive model who will be the development of the modified GTN model which is used in concrete for the dynamic constitutive model. The model takes into account of the rate of associated plastic flow, plastic strain hardening and softening, tension and compression damage.(2) For inclusion and items of the yield criterion, this thesis based on Simo and Aravas theory of the proposed algorithm is derived with Cauchy stress, porosity, and matrix equivalent stress of a total of eight variables within the implicit stress update algorithm in Lagamine program. Based on Fortran77 language write constitutive model subroutine CONDMG2 using three-dimensional solid elements.(3) The impact of load on the mechanical behavior of concrete columns under simulated to verify the validity and applicability.