Analysis of inertia and scale effects on dynamic neck formation during tension of sheet steel

Abstract It is well known that a specimen for impact testing must be optimized in terms of its dimensions. The main reason is to reduce strain gradients due to the effects of elastic–plastic wave propagation. On the other hand, when a split Hopkinson bar in tension is applied, the net displacement of the specimen ends is very limited, usually from 2.0 to 3.0 mm. Thus, to reach a maximum strain of 0.5 the specimen length must be reduced in dimensions from 4.0 to 6.0 mm. Consequently, small diameters or lateral dimensions and lengths must be applied to assure one-dimensional deformation. Such small lengths substantially perturb the determination of real material behavior. So the main motivation of this study was to perform a systematic analysis, numerical and analytical, to find differences in the behavior of short and long specimens loaded in impact tension. The finite element code ABAQUS/Explicit has been used to simulate several specimen lengths from 10 to 40 mm submitted to impact velocities ranging from 10 to 100 m/s.

[1]  J. Fernández-Sáez,et al.  An implicit consistent algorithm for the integration of thermoviscoplastic constitutive equations in adiabatic conditions and finite deformations , 2006 .

[2]  Amos Gilat,et al.  A direct-tension split Hopkinson bar for high strain-rate testing , 1991 .

[3]  T. Nicholas.  Tensile testing of materials at high rates of strain , 1981 .

[4]  J. D. Campbell,et al.  Tensile Testing of Materials at Impact Rates of Strain , 1960 .

[5]  J. Klepaczko.  Generalized conditions for stability in tension tests , 1968 .

[6]  M. Montagnani,et al.  Testing techniques based on the split Hopkinson bar , 1974 .

[7]  J. Duffy,et al.  Strain Rate History Effects in Body-Centered-Cubic Metals , 1982 .

[8]  Glenn S. Daehn,et al.  Effect of velocity on flow localization in tension , 1996 .

[9]  J. Klepaczko,et al.  Numerical study of shear deformation in Ti–6Al–4V at medium and high strain rates, critical impact velocity in shear , 2002 .

[10]  Ramón Zaera,et al.  Finite element simulation of steel ring fragmentation under radial expansion , 2007 .

[11]  Pol Duwez,et al.  The Propagation of Plastic Deformation in Solids , 1950 .

[12]  J. Klepaczko.  Review on critical impact velocities in tension and shear , 2005 .

[13]  Han Zhao.  A constitutive model for metals over a large range of strain rates : Identification for mild-steel and aluminium sheets , 1997 .

[14]  Fusahito Yoshida,et al.  Elastic-plastic behavior of steel sheets under in-plane cyclic tension-compression at large strain , 2002 .

[15]  C. Y. Wang,et al.  Validity of one-dimensional experimental principle for flat specimen in bar–bar tensile impact apparatus , 2000 .

[16]  Hoon Huh,et al.  A tension split Hopkinson bar for investigating the dynamic behavior of sheet metals , 2002 .

[17]  J. R. Klepaczko,et al.  Shear testing of a sheet steel at wide range of strain rates and a constitutive relation with strain-rate and temperature dependence of the flow stress , 2001 .

[18]  G. R. Johnson,et al.  Fracture characteristics of three metals subjected to various strains, strain rates, temperatures and pressures , 1985 .

[19]  L. M. Yeakley,et al.  High strain-rate testing: Tension and compression , 1968 .

[20]  R. Armstrong,et al.  Dislocation-mechanics-based constitutive relations for material dynamics calculations , 1987 .

[21]  G. Taylor,et al.  The Emission of the Latent Energy due to Previous Cold Working When a Metal is Heated , 1937 .

[22]  P. S. Symonds,et al.  SURVEY OF METHODS OF ANALYSIS FOR PLASTIC DEFORMATION OF STRUCTURES UNDER DYNAMIC LOADING , 1967 .

[23]  W. W. Wood.  Experimental mechanics at velocity extremes —Very high strain rates , 1967 .