CONSTITUTIVE EQUATIONS FOR ANNEALED AND EXPLOSIVELY SHOCKED IRON FOR APPLICATION TO HIGH STRAIN RATES AND LARGE STRAINS

The freely expanding ring test (ERT) is a conceptually simple test for determining the stress-strain behavior of materials at large strains and at high strain rates. This test is conducted by placing a thin ring of test material in a state of uniform radial expansion and then measuring its subsequent velocity-time history. The ring is usually propelled by a high explosive driving system. The test has not become popular in the materials property community, however, because there has been some concern about how the launching of the ring sample with an explosively generated shock wave might affect the properties to be measured. To determine the suitability of the ERT for these fundamental investigations, a series of experiments was performed on a carefully controlled material—oxygen-free electronic fully annealed copper. Recovered ring samples were analyzed and the change in hardness determined. Comparisons of the ERT data with that from Hopkinson bar tests at strain rates of about 5 × 103 s−1 indicate that the shock-induced hardness is approximately equivalent to a strain hardening of 5 percent. ERT data on this material at strain rates up to 2.3 × 104 s−1 are presented.

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A physically-based constitutive model applied to AA6082 aluminium alloy at large strains, high strain rates and elevated temperatures

Materials & Design ◽

10.1016/j.matdes.2016.04.047 ◽

2016 ◽

Vol 103 ◽

pp. 391-405 ◽

Cited By ~ 21

Author(s):

V. Vilamosa ◽

A.H. Clausen ◽

T. Børvik ◽

B. Holmedal ◽

O.S. Hopperstad

Keyword(s):

Constitutive Model ◽

Aluminium Alloy ◽

Elevated Temperatures ◽

High Strain ◽

Large Strains ◽

Strain Rates ◽

High Strain Rates ◽

Physically Based

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MATERIAL CHARACTERIZATION BY AN INNOVATIVE BIAXIAL SHEAR EXPERIMENT AT VERY LARGE STRAINS AND AT VERY HIGH STRAIN RATES

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:1991361 ◽

1991 ◽

Vol 01 (C3) ◽

pp. C3-435-C3-440

Author(s):

C. ALBERTINI ◽

L. J. GRIFFITHS ◽

M. MONTAGNANI ◽

A. RODIS ◽

P. MARIOTTI ◽

...

Keyword(s):

Material Characterization ◽

High Strain ◽

Large Strains ◽

Strain Rates ◽

High Strain Rates ◽

Very High

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Dynamic Constitutive Equations and Behaviour of Brass at High Strain Rates

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/pime_proc_1995_209_155_02 ◽

1995 ◽

Vol 209 (4) ◽

pp. 287-293 ◽

Cited By ~ 5

Author(s):

L-Y Li ◽

T C K Molyneaux

Keyword(s):

Flow Stress ◽

Strain Rate ◽

Yield Stress ◽

Constitutive Equations ◽

High Strain ◽

Strain Curve ◽

Strain Rates ◽

Stress Strain Curve ◽

High Strain Rates ◽

Stress Strain

This paper presents an experimental study of the mechanical properties of brass at high strain rates. The brass tested is the copperzinc alpha-beta and beta two-phase alloy in the cold-worked state. Experiments were conducted using an extended tension split Hopkinson bar apparatus. It is found that, at lower strain rates, the stress-strain curve is smooth, exhibiting no well-defined yield stress, but at higher strain rates the stress-strain curve not only shows a well-defined yield stress but also displays a very pronounced drop in stress at yield. The flow stress is found to increase with increasing strain rate, but the increase is more significant for the yield stress than for the flow stress, showing that the yield stress is more sensitive to the strain rate than the flow stress away from the yield point. Based on the experimental results, empirical strain-rate-dependent constitutive equations are recommended. The suggested constitutive equations provide a reasonable estimate of the strain-rate-sensitive behaviour of materials.

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