A Study of Dynamic Properties of S355J2 Steel and Y925 Tungsten Alloy

Authors:

  • Geng Sheng Wang

Publish date: 2021-07-06

Report number: FOI-R--4941--SE

Pages: 52

Written in: English

Keywords:

  • S355J2
  • Y925
  • mechanical property
  • strain rate
  • fracture locus
  • Hosford- Coulomb
  • Johnson Cook
  • material tests
  • yield criterion

Abstract

In this study, efforts have been made to characterize the dynamic strength and failure properties of S355J2 steel and Y925 alloy for security and defence applications. Material tests and hybrid analyses of the results have been performed. The activity includes both the design of tests and analyses of the results. A simulation based method to analyse dynamic test results is developed for high strain rate tests using the Hopkinson single bar impactor and Kosky split bar apparatus. With the help of the system method, it is shown that material parameters can be identified with tailor made specimens for specific material model. The critical values for different failure patterns are determined for different material models for ballistic applications when the high strain rate impulse load and adiabatic heating are important considerations. The study includes complex fracture patterns that are often of a great concern. With the developed method, parameters for Johnson-Cook models for both material have been determined and validated for the effect of strain rate hardening and temperature softening. In addition, parameters for an advanced fracture model, the Hosford-Mohr-Coulomb failure models, are determined for S355J2 steel based on the material test results.