Finite Element Analysis on a Newly-Modified Method for the Taylor Impact Test to Measure the Stress-Strain Curve by the Only Single Test Using Pure Aluminum

• Published in: Metals (Basel ) 2018-08, Vol.8 (8), p.642
• Main Authors: Gao, Chong, Iwamoto, Takeshi
• Format: Article
• Language: English
• Subjects: Aluminum; Axial stress; Computer simulation; Deformation; External pressure; Finite element analysis; Finite element method; finite element simulation; Friction; Hardening rate; Hopkinson pressure bar; Impact loads; Impact tests; Internal forces; Mathematical analysis; Mechanical properties; miniaturized testing apparatus; Parameter identification; Parameter sensitivity; Rigid walls; Split Hopkinson pressure bars; Strain rate; stress-strain curve; Stress-strain curves; Stress-strain relationships; Taylor impact test; Test equipment; Validity
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met8080642

In this study, finite element analyses are performed to obtain a stress-strain curve for ductile materials by a combination between the distributions of axial stress and strain at a certain time as a result of one single Taylor impact test. In the modified Taylor impact test proposed here, a measurement of the external impact force by the Hopkinson pressure bar placed instead of the rigid wall, and an assumption of bi-linear distribution of an axial internal force, are introduced as well as a measurement of deformed profiles at certain time. In order to obtain the realistic results by computations, at first, the parameters in a nonlinear rate sensitive hardening law are identified from the quasi-static and impact tests of pure aluminum at various strain rates and temperature conducted. In the impact test, a miniaturized testing apparatus based on the split Hopkinson pressure bar (SHPB) technique is introduced to achieve a similar level of strain rate as 104 s−1, to the Taylor test. Then, a finite element simulation of the modified test is performed using a commercial software by using the user-subroutine for the hardening law with the identified parameters. By comparing the stress-strain curves obtained by the proposed method and direct calculation of the hardening law, the validity is discussed. Finally, the feasibility of the proposed method is studied.