Determination of Johnson Cook parameters for Ti-6Al-4 V Grade 5 experimentally by using three different methods

Abstract

Accurate results can be obtained from numerical simulation only when it replicates or rather simulates the actual machining process as precisely as possible. To achieve the closest precision; boundary conditions, material model and mechanical material properties should be provided properly to the simulation file. Among all the material models, Johnson Cook material model is relatively simple to use. Every process operates under several loading condition with different deformation temperature and these values are different for different materials. For the successful simulation it is essential to have knowledge of exact Johnson Cook model parameters used for respective process and material at its operating temperature and strain rate. In this paper, Johnson Cook model parameters for Ti-6Al-4 V Grade 5 are found experimentally with strain rates as 1 × 10 −4 s −1 , 1.5 × 10 −4 s −1 , 1 × 10 −3 s −1 and 1.5 × 10 −3 s −1 and elevated temperature variations of 200 °C, 300 °C, 400 °C, 800 °C, 1000 °C, 1200 °C and at room temperature. Tensile test is conducted as it is the most suitable and cost effective among all to find properties, properties found are further used to find JC parameters by using three different methods: regression analysis method, least square method and logarithmic plot graph method. Values obtained after using all three methods are compared with each other and it is found that the deviation in values is not wide enough to hinder the results. This ensures that the researcher can practice whichever method is convenient to them according to their expertise.