High strain rate material characterization of Al 7075-T651 by modified Taylor impact test and velocity interferometry


Kesemen L., Kayran A.

58th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, 2017, Texas, United States Of America, 9 - 13 January 2017 identifier

  • Publication Type: Conference Paper / Full Text
  • Volume:
  • Doi Number: 10.2514/6.2017-0354
  • City: Texas
  • Country: United States Of America

Abstract

© 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.Metallic materials in aerospace structures are exposed to impact loading depending on their usage area. High strain rate material characterization of metallic materials is very crucial to properly prepare finite element models to be used in impact loading situations. Aluminum alloys are widely used in aerospace structures in variety of areas. Johnson-Cook material model is a suitable material model to represent the behaviour of aluminum alloys at high strain rates. In the present study, parameters of the Johnson-Cook yield strength model for the Al 7075-T651 material are determined utilizing the combination of the quasi-static tensile test and the modified Taylor impact test. High strain rate material characterization of Al 7075-T651 is performed by the modified Taylor impact test and velocity interferometry. Modified Taylor impact test system and how the free surface velocity measurement by the velocity interferometry is utilized for the determination of the yield strength and the strain rate constant of the Johnson-Cook yield strength model are described in detail. Experimentally determined parameters of the Johnson-Cook model are used in Autodyn simulation of the modified Taylor impact test. Experimentally and numerically determined free surface velocities are compared and reasonably good agreement is obtained between the test and simulation results with a small offset between the velocity profiles.