Plastic deformation of high-purity a-titanium: model development and validation using the Taylor cylinder impact test

10th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes

Chandola, Nitin^1 ; Revil-Baudard, Benoit^1 ; Cazacu, Oana^1

Department of Mechanical and Aerospace Engineering, University of Florida, REEF, 1350 N. Poquito Rd., Shalimar

FL

32579, United States^1

关键词: Quasi-static conditions;    Split Hopkinson Pressure Bar test;    Strain rate sensitivity;    Strength-differential effects;    Tension and compression;    Tension-compression asymmetry;    Transversely isotropic;    Uni-axial compression;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/734/3/032048/pdf
DOI  :  10.1088/1742-6596/734/3/032048

来源: IOP

【 摘 要 】

Results of an experimental study on the quasi-static and high-rate plastic deformation due to impact of a high-purity, polycrystalline, a-titanium material are presented. To quantify the plastic anisotropy and tension-compression asymmetry of the material, first monotonic uniaxial compression and tension tests were carried out at room temperature under quasi-static conditions. It was found that the material is transversely isotropic and displays strong strength differential effects. To characterize the material's strain rate sensitivity, Split Hopkinson Pressure Bar tests in tension and compression were also conducted. Taylor impact tests were performed for impact velocity of 196 m/s. Plastic deformation extended to 64% of the length of the deformed specimen, with little radial spreading. To model simultaneously the observed anisotropy, strain-rate sensitivity, and tension-compression asymmetry of the material, a three-dimensional constitutive model was developed. Key in the formulation is a macroscopic yield function [1] that incorporates the specificities of the plastic flow, namely the combined effects of anisotropy and tension-compression asymmetry. Comparison between model predictions and data show the capabilities of the model to describe with accuracy the plastic behavior of the a-Ti material for both quasi-static and dynamic loadings, in particular, a very good agreement was obtained between the simulated and experimental post-test Taylor specimen geometries.