Dynamic Compressive Tests of Alumina Dumbbells Using a Spherical Joint

  • Steven MatesEmail author
  • Richard Rhorer
  • George Quinn
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)


The dynamic compressive strength of ceramic armor materials is difficult to obtain experimentally due to the sensitivity of fracture strength to small misalignments, end effects, and surface effects. In this work we introduce a spherical joint into a compression Kolsky bar to investigate whether the joint can alleviate bending stresses due to minor misalignment in compression tests on alumina dumbbell specimens. Tests are conducted both with and without the spherical joint, and high-speed (75,000 frames/s) three-dimensional Digital Image Correlation (3D DIC) is used to measure both the strain field on the dumbbell specimen and motion, if any, in the spherical joint. Results indicate that the spherical joint is extremely sensitive to eccentric loading and in most cases increases rather than decreases the bending stresses in the test, leading to lower apparent fracture strengths.


Kolsky bar Dynamic fracture strength Dumbbell specimens 3D DIC High-speed video 



Dr. Jeffrey Swab, U.S. Army RDECOM, for inviting us to participate in the round robin and for valuable discussions.


  1. 1.
    Chen, W., Song, B.: Split Hopkinson (Kolsky) Bar: Design, Testing and Applications, p. 2011, New York (2011). ISSN 0941-5122Google Scholar
  2. 2.
    Jones, E.M.C., Iadicola, M.A.: A Good Practices Guide for Digital Image Correlation. s.l. International Digital Image Correlation Society (2018)Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 2020

Authors and Affiliations

  1. 1.National Institute of Standards and TechnologyGaithersburgUSA
  2. 2.Rhorer Precision EngineeringGaithersburgUSA

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