On the Measurement of Local Strain and Temperature During the Formation of Adiabatic Shear Bands in Steels
On the Measurement of Local Strain and Temperature During the Formation of Adiabatic Shear Bands in Steels

Author: Y. C. Chi

Publisher:

Published: 1969

Total Pages: 113

ISBN-13:

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An experimental study was conducted to determine local strain, local strain rate, and temperature distribution within an adiabatic shear band during its formation. Thin-walled tubular specimens were deformed at dynamic rates in a torsional Kolsky bar (torsional split-Hopkinson bar) and direct observation of the strain localization process was made through ultra high-speed photography of a grid pattern deposited on the specimen's surface. Temperature measurements were effected using an array of sixteen infrared radiation detectors. The optical system employed allows each detector to focus on a band 17 micrometers wide. Three different steels were tested: (1) an AISI 1018 cold rolled steel, (2) a low alloy structural steel (HY-100), and (3) an AISI 4340 VAR steel tempered to either of two hardnesses, HRC 44 or 55. The principal goal of the investigation was to relate initial geometric defects in specimen geometry to the timing of stress collapse during shear band development. A comparison of experimental results with predictions based on the analysis of Molinari and Clifton showed good agreement. In addition, quasi-static tests on the same materials revealed two significant differences between dynamic and quasi-static plastic deformation. First, localization of strain into a shear band occurs in dynamic deformation, but never quasi-statically, and second, the magnitude of the strain fracture is always considerably greater in quasi-static deformation than dynamically. (kt).

Adiabatic Shear Localization
Adiabatic Shear Localization

Author: Bradley Dodd

Publisher: Elsevier

Published: 2012-05-22

Total Pages: 469

ISBN-13: 0080977812

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Rev. ed. of: Adiabatic shear localization / Y. Bai and B. Dodd. 1992. 1st ed.

An Experimental Study of the Formation Process of Adiabatic Shear Bands in a Structural Steel
An Experimental Study of the Formation Process of Adiabatic Shear Bands in a Structural Steel

Author: A. Marchand

Publisher:

Published: 1987

Total Pages: 65

ISBN-13:

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A series of experiments is described in which the local temperature and local strain are measured during the formation of an adiabatic shear band in a low alloy structural steel (HY-100). The specimen employed consists of a short thin-walled tube and the required rapid deformation rates are imposed by loading the specimen in a torsional Kolsky bar (split-Hopkinson bar). The local temperature is determined by measuring the infrared radiation emanating at twelve neighboring points on the specimen's surface, including the shear band area. Indium-antimonide elements are employed for this purpose to give the temperature history during deformation. In addition, high speed photographs are made of a grid pattern deposited on the specimen's surface, thus providing a measure of the strain distribution at various stages during shear band formation. By testing a number of specimens, it is possible to form a picture of the developing strain localization process, of the temperature history within the forming shear band, and of the consequent loss in the load carrying capacity of the steel. Reprints. (jes).

Shock Wave and High-Strain-Rate Phenomena in Materials
Shock Wave and High-Strain-Rate Phenomena in Materials

Author: 0 Meyers,

Publisher: CRC Press

Published: 2023-07-21

Total Pages: 1852

ISBN-13: 1000950190

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These proceedings of EXPLOMET 90, the International Conference on the Materials Effects of Shock-Wave and High-Strain-Rate Phenomena, held August 1990, in La Jolla, California, represent a global and up-to-date appraisal of this field. Contributions (more than 100) deal with high-strain-rate deforma

Continuum Thermomechanics
Continuum Thermomechanics

Author: Paul Germain

Publisher: Springer Science & Business Media

Published: 2000-08-31

Total Pages: 428

ISBN-13: 0792364074

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Contributed by world-renowned specialists on the occasion of Paul Germain's 80th birthday, this unique book reflects the foundational works and the intellectual influence of this author. It presents the realm of modern thermomechanics with its extraordinary wealth of applications to the behaviour of materials, whether solid or fluid. The thirty-one contributions follow an easygoing autobiographical sketch by Paul Germain, and highlight the power and richness of a methodological approach to the phenomenology of many materials. This approach combines harmoniously thermodynamics and continuum theory in order to provide exploitable, thermodynamically admissible models of a large variety of behaviours and phenomena, including those of diffusion, thermoelasticity, viscoplasticity, relaxation, hysteresis, wetting, shape-memory effects, growth, phase transitions, stability, fracture, shocks, machining of materials, microstructured solids, complex fluids, etc. Especially aimed at graduate students, researchers, and engineers in mechanical engineering and materials science, this book also presents the state of the art in an active field of research and opens new horizons in other scientific fields, such as applied mathematics and applied physics, because of the intellectual satisfaction and remarkable efficiency provided by the advocated approach.

Measurement of the Temperature Profile During Shear Band Formation in Steels Deforming at High Strain Rates
Measurement of the Temperature Profile During Shear Band Formation in Steels Deforming at High Strain Rates

Author:

Publisher:

Published: 1986

Total Pages: 62

ISBN-13:

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A torsional Kolsky bar (split-Hopkinson bar) was used to deform tubular specimens of AISI 1018 cold rolled steel and AISI 1020 hot rolled steel at a nominal strain of 10 to the 3th power per s. Shear bands were observed to form in both steels and the temperature of the material in the bands was measured by determining the infrared radiation emitted at the metal surface. For this purpose, a linear array of ten indium-antimonide detectors was used to determine temperature history at ten neighboring points lying across the projected path of the shear band. Results showed that shear bands in these low carbon steels are relatively wide, that the maximum temperature rise in the band is about 450 C and that the temperature distribution across the band is consistent with results based on an analysis performed by Shawki and Clifton. The two steels have very different work hardening rates and the strain at which localization is first observed is very different for the two steels: in the cold-rolled steel it occurs at about 15% strain, while in the hot-rolled the strain is nearer 100%. This result also is consistent with predictions based on the analysis.