NUMERICAL MODELING OF THE CHARPY TEST, AN IMPROVING WAY OF OBTAINED RESULTS BY THE EXPERIMENTAL METHOD

摘要

Nowadays, the numerical modeling of the behavior of different materials has a great importance for analysis of the structure responding, especially over the elastic limit and under dynamic conditions. There is some material models used in finite element analysis, like Johnson-Cook, Simplified Johnson-Cook, Krieger (Cowper-Symond), Picewise-linear plasticity, Needleman-Tvergaard, Zerilli-Armstrong, Shirakashi-Vinh etc. For using of these material models, we have to know the material constants - a very important problem. Numerical simulation being used, in a good concordance with the experiment, a lot of studies can be made regarding to a material class, upon influence of different material constant on the simulation result and even to put in evidence how we could improve the material properties under dynamic loading. The study, presented in this work, is basing on Ls-Dyna code and on some material models, most used in our opinion, like plastic-kinematic, Johnson-Cook and Picewise-linear plasticity. The Charpy test - an experimental dynamic test - can be modeled using such material models. After a right numerical modeling of this test, having a much closed result with the experiment, we could obtain a lot of information about the influence of different material constants upon the numerical results.