Abstract
In this study, occurrence of adiabatic shear bands in AISI 4340 steel under high velocity impact loads is investigated using finite element analysis and experimental tests. The cylindrical steel specimen subjected to impact load was divided into different sections separated by nodes using finite element method in ABAQUS environment with boundary conditions specified. The material properties were assumed to be lower at the section where the adiabatic shear bands are expected to initialize. The finite element model was used to determine the maximum flow stress, the strain hardening, the thermal softening, and the critical strain for the formation of adiabatic shear bands. Experimental results show that deformed bands were formed at low strain rates and there was a minimum strain rate required for formation of transformed band in the alloy. The experimental results also show that cracks were initiated and propagated along transformed bands leading to fragmentation under the impact loading. The susceptibility of the adiabatic shear bands to cracking was markedly influenced by strain-rates. The simulation results obtained were compared with experimental results obtained for the AISI 4340 steel under high strain-rate loading in compression using split impact Hopkinson bars. A good agreement between the experimental and simulation results was obtained.
Highlights
During impact loading, heat is generated as a result of the conversion of kinetic energy of the projectile to heat energy during deformation
The experimental results show that cracks were initiated and propagated along transformed bands leading to fragmentation under the impact loading
As a result of severe plastic deformation occurring along adiabatic shear bands (ASBs), these bands consist of intensely distorted grains or fragmented grains in metallic materials exposed to high strain-rate deformation [1]
Summary
Heat is generated as a result of the conversion of kinetic energy of the projectile to heat energy during deformation. Strain localization leading to formation of adiabatic shear bands is peculiar to metallic materials This phenomenon has been observed in ceramic materials [6,7] and polymeric materials [7,8] after exposure to dynamic shock loading. Observations of transformed adiabatic shear bands using transmission electron microscope in many materials indicate that they consist of very fine grains of submicron size [14]. The Zerilli and Armstrong model is a dislocation pile up model where the blocking of dislocation on a slip plane by obstacles leads to extensive strain causing the formation of bands This model uses dislocation mechanics concept to develop flow stress method in accounting for strain rate, strain, and temperature during dynamic impact loading. The characteristics of adiabatic shear bands observed in the impacted steel alloy were investigated in relation to the pre-impact microstructure of the steel specimens
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
