A history of Hopkinson bars in Europe

transcript

Stephen Walley

Cavendish Laboratory, University of Cambridge, UK

Acknowledgements

Thanks to:

Tony Andrews, Ezio Cadoni, Stuart Clyens, Hervé Couque, Bradley Dodd, John Field, Gérard Gary, Stefan Hiermaier, Leopold Kruszka, Erhardt Lach, Jean-Luc Lataillade, Lothar Meyer, Vitali Nesterenko, Reinhard Tham

Overview

1. Who was Bertram Hopkinson? 2. Origins of high strain rate testing 3. Origins of the split Hopkinson bar in the UK 4. Developments in the UK since Kolsky 5. Concrete and structures 6. Soft materials (few MPa strengths) 7. Two-point measurement and rocks 8. Surface temperature measurement techniques 9. Developments in Germany 10. Developments in Russia (USSR) 11. Developments in France 12. Summary

European countries mentioned in this presentation

United Kingdom France

Germany Poland

Russia (USSR) Czechoslovakia

Italy Sweden Spain

Denmark

Histogram of split Hopkinson bar papers to 2012

1. Who was Bertram Hopkinson ?

1. Professors Hopkinson Father & Son

1849-1898. Died falling off a mountain in the Alps

1894-1918. Brought down by a thunderstorm in Surrey while

piloting his own plane

1. Plaque to the memory of John Hopkinson in Free School Lane, Cambridge

1. From Bertram Hopkinson’s obituary in Proc. R. Soc. Lond. A 95 (1919) xxvi-xxxvi

1. From the ‘Alpine Journal’

1. Orfordness

1. Orfordness: Last military use

Bunker for testing atomic bombs for shake, rattle and roll!

1. From Bertram Hopkinson’s obituary in Proc. R. Soc. Lond. A 95 (1919) xxvi-xxxvi

1. Hopkinson’s motivation: Measuring pulse shapes

Phil. Trans. R. Soc. Lond. A 213 (1914) 437-456

1. Notice to members of King’s College Cambridge of Bertram Hopkinson’s funeral

1. King’s College Chapel

1. Choir of King’s College Chapel

1. Entrance to the War Memorial side chapel

1. King’s College First World War memorial

1. Bertram Hopkinson’s final resting place, St Giles Cemetery, Cambridge

1. Frontispiece to his collected papers

1. Finally from the ‘Alpine Journal’

2. Origins of high strain-rate testing

•  1872, Hopkinson, J. "On the rupture of iron wire by a blow" Proc. Manchester Literary Philosophical Society 11 40-45

•  1872, Hopkinson, J. "Further experiments on the rupture of iron wire" Proc. Manchester Literary Philosophical Society 11 119-121

•  1876, Pochhammer, L. "Über Fortpflanzungsgeschwindigkeiten kleiner Schwingungen in einem unbegrenzten isotropen Kreiszylinder" J. reine angew. Math. 81 324-336

•  1886, Chree, C. "Longitudinal vibrations of a circular bar" Quart. J. Pure Appl. Math. 21 287-298

2. John Hopkinson’s wire experiment (1872)

J. Hopkinson, Proc. Manchester Literary Philosophical Society 11 (1872) 40-45, 199-121

•  1883, de Saint Venant, A.J.C.B. and Flamant, A. "Résistance vive ou dynamique des solides: Représentation graphique des lois du choc longitudinal, subi à une des extrémités par une tige ou barre prismatique assuiettie à l'extrémités opposée" C.R. Acad. Sci. 97 127-133

•  1897, Dunn, B.W. "A photographic impact testing machine for measuring the varying intensity of an impulsive force" J. Franklin Inst. 144 321-348

•  1899, Chree, C. "Longitudinal vibrations in solid and hollow cylinders" Proc. Phys. Soc. Lond. 16 304-322

•  1905, Hopkinson, B. "The effects of momentary stresses in metals" Proc. R. Soc. Lond. 74 498-506 (repeat of experiments performed by his father, J. Hopkinson)

•  1907, Sears J.E. “On the longitudinal impact of metal rods with rounded ends” Proc. Camb. Philos. Soc. 14 257-286

First known graph of difference between static and dynamic compressive strength of a metal.

B.W. Dunn, J. Franklin Inst. 144 (1897) 321-348 (and subsequent discussion in J. Franklin Inst. 145 (1898) 36-47

•  1914, Hopkinson, B. "The effects of the detonation of gun-cotton" Trans. North-East Coast Inst. Engineers Shipbuilders 30 199-217

•  1914, Hopkinson, B. "A method of measuring the pressure produced in the detonation of high explosives or by the impact of bullets" Phil. Trans. R. Soc. Lond. A213 437-456

•  1921, Hopkinson, B. "The pressure of a blow", in "The Scientific Papers of Bertram Hopkinson", ed. J.A. Ewing and J. Larmor, pp. 423-437, publ. Cambridge University Press

•  1923, Landon, J.W. and Quinney, H. "Experiments with the Hopkinson pressure bar" Proc. R. Soc. Lond. A103 622-643

2. Original Hopkinson bar

B. Hopkinson, Phil. Trans. R. Soc. Lond. A 213 (1914) 437-456

2. Data that Hopkinson obtained

2. Hopkinson fracture

Hopkinson, B. "The effects of the detonation of gun-cotton" Trans. North-East Coast Inst. Engineers Shipbuilders 30

(1914) 199-217

2. First paper to name the Hopkinson pressure bar

1923, Landon, J.W. and Quinney, H. Proc. R. Soc. Lond. A103 622-643

2. First paper to name the Hopkinson pressure bar

1923, Landon, J.W. and Quinney, H. Proc. R. Soc. Lond. A103 622-643

2. Robertson’s comments on the importance of Hopkinson’s bar to the study of explosives in WW1

Robertson, R. (1921) “Some war developments of explosives” Nature 107 524-527

3. Origins of the split Hopkinson pressure bar in the UK

•  1946, Taylor, G.I. "The testing of materials at high rates of loading" J. Inst. Civil Engrs 26 486-519

•  1948, Volterra, E. "Alcuni risultati di prove dinamiche sui materiali (Some results on the dynamic testing of materials)" Rivista Nuovo Cimento 4 1-28

•  1948, Davies, R.M. "A critical study of the Hopkinson pressure bar" Phil. Trans. Roy. Soc. Lond. A240 375-457

•  1949, Kolsky, H. "An investigation of the mechanical properties of materials at very high rates of loading" Proc. Phys. Soc. Lond. B 62 676-700

3. First use of Hopkinson bars in high rate compression testing

3. Enrico Volterra 1905-1973

b. 1905 in Rome. Lived in the UK 1938-1946 where he worked with G.I. Taylor at Cambridge on plastics and rubbers. Returned to Italy 1946. Moved to the United States in 1948. d. 1973 in Austin, Texas

Volterra in military uniform in the 1920s

3. G.I. Taylor

7 March 1886 – 27 June 1975

3. Volterra apparatus

E. Volterra, Rivista Nuovo Cimento 4 (1948) 1-28

3. High strain rate results for polyethylene from Volterra’s apparatus as reported by G.I. Taylor in 1946

G.I. Taylor, J. Inst. Civil Engrs 26 (1946) 486-519

3. Davies’ use and analysis

R.M. Davies, Phil. Trans. R. Soc. Lond. A240 (1948) 375-457

3. Davies’ use and analysis

R.M. Davies, Phil. Trans. R. Soc. Lond. A240 (1948) 375-457

3. Kolsky’s bar

H. Kolsky, Proc. Phys. Soc. Lond. B 62 (1949) 676-700

3. Herbert Kolsky 1917-1992

•  Graduated in Physics from Imperial College, London in 1937

•  Did war-related research at Imperial College during World War 2

•  Head of Physics at ICI Butterwick Research Laboratories, Welwyn until 1956

•  Visiting Professor at Brown University, USA, 1956-1958

•  Senior Principal Scientific Officer at RARDE Fort Halstead, Sevenoaks, Kent 1958-1960

•  Professor of Applied Mathematics and Engineering, Brown University, USA 1960-1992

3. Kolsky’s bar

H. Kolsky, Proc. Phys. Soc. Lond. B 62 (1949) 676-700

3. First split Hopkinson bar of modern design

Proc. R. Soc. Lond. A221 (1954) 114-127

3. First split Hopkinson bar of modern design

Proc. R. Soc. Lond. A221 (1954) 114-127

3. First high strain rate conference 1957

No split Hopkinson pressure bar papers.

But two papers from Oxford where

a hybrid dropweight-Hopkinson bar apparatus was reported (also one from the United States that

utilized a similar technique).

3. First Oxford high rate conference 1974

Contains 9 papers on SHPB compression tests on metals: USA 3, UK 3, Italy 1, Australia 1, Japan 1

3. First international DYMAT conference 1985

Contains 24 papers on SHPB tests: 15 on metals 4 on polymer composites 2 on polymers 2 on explosives 1 on ceramics Countries that reported SHPB tests: France 10 USA 3 UK 3 Italy 2 China 1 Czechoslovakia 1 Sweden 1

4. Developments in the UK since Kolsky

4. Oxford University Engineering Department’s hybrid apparatus

From: J.D. Campbell, J. Mech. Phys. Solids 3

(1954) 54-62

First published in: J.D. Campbell, J. Mech. Phys. Solids 1

(1953) 113-123

4. Fort Halstead, UK

Hunter, S.C. and Davies, E.D.H. (1960) “The dynamic compression testing of solids by the methods of the split Hopkinson pressure bar. 1: The theoretical

nature of the experiment”, War Office Report no. (MX) 7/60, Armament Research and Development Establishment, Sevenoaks, Kent

Hunter, S.C. and Davies, E.D.H. (1960) “The dynamic compression testing of

solids by the methods of the split Hopkinson pressure bar. 2: Experimental observations of soft metals and polymer materials”, War Office Report no.

(MX) 8/60, Armament Research and Development Establishment, Sevenoaks, Kent

4. Fort Halstead, UK

E.D.H. Davies & S.C. Hunter, J. Mech. Phys. Solids 11 (1963) 155-179

•  1960, Harding, J., Wood, E.O. and Campbell, J.D. "Tensile testing of materials at impact rates of strain" J. Mech. Engng Sci. 2 88-96

•  1963, Davies, E.D.H. and Hunter, S.C. "The dynamic compression testing of solids by the method of the split Hopkinson pressure bar (SHPB)" J. Mech. Phys. Solids 11 155-179

4. Tension (Oxford) and compression (Fort Halstead)

4. Cambridge University Engineering Department

J. Harding, Arch. Mech. Stos. 27 (1975) 715-732

4. Inertia: data for titanium

•  1980, Gorham, D.A. "Measurement of stress-strain properties of strong metals at very high strain rates" Inst. Phys. Conf. Ser. 47 16-24

•  1992, Gorham, D.A., Pope, P.H. and Field, J.E. "An improved method for compressive stress-strain measurements at very high strain rates" Proc. R. Soc. Lond. A 438 153-170

4. Miniaturisation

Miniaturisation reduces:

(i) Inertia of specimen

(ii) Dispersion in pressure bar

(iii) Time to stress equilibrium

(iv) Impact velocity to achieve a given strain rate

4. Benefits of miniaturisation

σ i = ρ

' ( ( ∂ε∂t

' ( ( ∂ 2ε∂t2

Radius a = 1.9mm, height h = 2.3mm Formula given in Gorham et al., Proc. R. Soc. Lond. A438 (1992) 153

4. Inertia and miniaturisation

Radial inertia sets upper bound on strain rate in 1D stress to ca. 105 s-1

4. Stress-strain curves for depleted uranium at 30,000 s-1

N.A. Safford, PhD thesis, University of Cambridge, 1988

4. Miniaturised Direct Impact Hopkinson Bar

4. Schematic of miniature direct impact apparatus

D.A. Gorham, Inst. Phys. Conf. Ser. 47 (1980) 16-21

4. Specimen size

4. DIHB titanium specimen after testing

Top view From: S.N. Mentha (1987), PhD thesis, Univ. Cambridge

4. Use of an optical wedge to improve accuracy

4. What the optical wedge does

4. Good lubrication

4. Poor lubrication

4. Plastic ‘waves’

4. Calculation compared to measurement

D.A. Gorham et al., Proc. R. Soc. Lond. A438 (1992) 153-170

4. Recent developments: Miniature SHPB used for an epoxy

J.L. Jordan et al., Mech. Time-Depend. Mater. 12 (2008) 249-272

4. Double notch shear specimen for fracture and shear band studies

1970, Campbell, J.D. and Ferguson, W.G. Philos. Mag. 21 63-82

4. Double notch shear specimen for fracture and shear band studies

1991, Ruiz, D.J., Harding, J. and Ruiz, C. J. Phys. IV France 1(C3) 465-470

Pure shear not obtained

4. Pulse shaping using a third (softer) bar

1995, Parry, D.J., Walker, A.G. and Dixon, P.R. "Hopkinson bar pulse smoothing" Meas. Sci. Technol. 6 443-446

4. Rate effects in polymers: polypropylene

0! 0.1! 0.2! 0.3! 0.4! 0.5! 0.6!

true strain!

1.12±0.01 s!-1!0.0151±0.0003 s!-1!

1360±13 s!-1!

16,500±1400 s!-1!

4770±140 s!-1!2145±5 s!-1!

27.8±0.8 s!-1!

10!-3! 10!-1! 10!1! 10!3! 10!5!

strain rate / s!-1!

S.M. Walley & J.E. Field, DYMAT Journal 1 (1994) 211

4. Rate effects in polymers: dry nylon 6

0! 0.1! 0.2! 0.3! 0.4! 0.5! 0.6!

0.020±0.003 s!-1!

true strain!

8900±60 s!-1!

2070±9 s!-1!20,300±250 s!-1!

28.2±0.1 s!-1!

1.14±0.01 s!-1!

10!-3! 10!-1! 10!1! 10!3! 10!5!St

strain rate / s!-1!

4. Rate effects in polymers: polyetheretherketone

0! 0.1! 0.2! 0.3! 0.4! 0.5! 0.6!

true strain!

5400±20 s!-1!1490±20 s!-1!788±13 s!-1!

17,600±750 s!-1!

0.0100±0.0002 s!-1!

26.6±0.2 s!-1!

1.12±0.006 s!-1!

10!-3! 10!-1! 10!1! 10!3! 10!5!St

strain rate / s!-1!

Balzer et al., Proc. R. Soc. Lond. A460 (2004) 781

4. Particle size effect in an AP/HTPB propellant @ -60˚C

J.E. Balzer et al. (2004), Proc. R. Soc. Lond. A460 781-806

J.E. Field et al., (2004), Mater. Res. Soc. Symp. Proc. 800 179-190

4. Optical techniques (speckle) to measure deformation of explosives

4. Effect of aspect ratio on tungsten

Top view 8mm diam., 4mm thick, 19.2 m/s, 50 ms interframe time From: S.M. Walley et al., J. Phys. IV France 134 (2006) 851-856

Top view

8mm diam., 10mm thick, 32.7 m/s, 100 ms interframe time From: S.M. Walley et al., J. Phys. IV France 134 (2006) 851-856

Top view

4mm diam., 8mm thick, 32.2 m/s, 100 ms interframe time From: S.M. Walley et al., J. Phys. IV France 134 (2006) 851-856

5. Concrete and structures

5. Italy: Largest Hopkinson bar in the world

•  1980, Albertini, C., Montagnani, M., Cenerini, R. and Curioni, S. "Radiation, welding, temperature and strain rate influence of material properties in fast breeder reactors" Arch. Mech. 32 549-577

•  1992, Albertini, C. and Montagnani, M. "Large Hopkinson's bar methods for advanced impact testing of steel and concrete structural components", in "Proc. Int. Symp. on Impact Engineering", ed. I. Maekawa, pp. 514-519, publ. Sendai, Japan, ISIE

•  1997, Albertini, C., Cadoni, E. and Labibes, K. "Impact fracture processes and mechanical properties of plain concrete by means of a Hopkinson bar bundle" J. Phys. IV France 7(C3) 915-920

Photo of Large Dynamic Testing Facility at ISPRA.

Originally developed for testing nuclear reactor materials and components at

high strain rates.

Capability: 200m length, 5MN load, 1.5m displacement, 35 m/s speed.

Latterly modified for impact testing of

automobile materials and structures for crashworthiness studies. Also road

safety barriers.

1 2 5 3

1112 13

6. Soft materials (few MPa strengths)

6. Special issues connected with testing soft materials in SHPBs

If the impedance of the specimen is significantly smaller than that of the bars, the transmitted signal will be small. This means that the signal-to-noise ratio will be poor making it difficult to check specimen equilibrium. Thus low impedance (e.g. magnesium) bars are increasingly being used for testing soft materials such as polymers and elastomers.

6. Comparison of SHPBs in Cambridge and LANL

6. Output bar signals for polycarbonate for three different bar types

0 50 100 150 200Time / µs

DuralSteelTungsten

C.R. Siviour et al., in “New Experimental Methods in Materials Dynamics and Impact”, ed. W.K. Nowacki & J.R. Klepaczko, pp. 421-427, publ. IPPT, Warsaw

6. Resulting stress-strain curves for polycarbonate at a strain rate of 4500 s-1

0 0.1 0.2 0.3 0.4 0.5S t r a i n

TungstenSteelDuralTSSDTD4

C.R. Siviour et al., in “New Experimental Methods in Materials Dynamics and Impact”, ed. W.K. Nowacki & J.R. Klepaczko, pp. 421-427, publ. IPPT, Warsaw

Proceeding from here:

A better output bar than magnesium AZM would be one with lower stiffness

Polymers are an option – but analysis is challenging, especially for non-ambient temperatures

A capped metal tube can achieve the required impedance

Simulations of cap effects on wave propagation would be necessary

6. Soft materials (courtesy of D.R. Drodge)

•  1994, Wang, L., Labibes, K., Azari, Z. and Pluvinage, G. "Generalization of split Hopkinson bar technique to use viscoelastic bars" Int. J. Impact Engng 15 669-686

•  1995, Gary, G., Klepaczko, J.R. and Zhao, H. "Generalization of split Hopkinson bar technique to use viscoelastic materials" Int. J. Impact Engng 16 529-530

•  1998, Bacon, C. "An experimental method for considering dispersion and attenuation in a viscoelastic Hopkinson bar" Exper. Mech. 38 242-249

6. Viscoelastic (polymer) bars

7. Two-point measurement and rocks

7. Sweden: Origins of 2-point measurement technique (originally for rock drilling)

•  1976, Lundberg B. "A split Hopkinson bar study of energy absorption in dynamic rock fragmentation" Int. J. Rock Mech. Min. Sci. 13 187-197

•  1977, Lundberg, B. and Henchoz, A. "Analysis of elastic waves from two-point strain measurement" Exper. Mech. 17 213-218

•  1990, Lundberg, B., Carlsson, J. and Sundin, K.G. "Analysis of elastic waves in non-uniform rods from two-point strain measurement" J. Sound Vibration 137 483-493

H. Zhao and G. Gary "A new method for the separation of waves: Application to the SHPB technique for an unlimited duration of measurement”

J. Mech. Phys. Solids 45 (1997) 1185-1202

7. Extending the time of measurement using two gauges

7. More on rocks: Czechoslovakia

•  1975, Buchar, J. and Dusek, F. "The influence of loading rate on mechanical properties of rocks" Arch. Mining Sci. 20 245-259

•  1976, Buchar, J., Dusek, F. and Svoboda, J. "The behaviour of rocks at stress wave loading" Dechema Monograph. 79 115-129

•  1981, Buchar, J. and Bilek, Z. "Application of the Hopkinson split bar test to the mechanical and fracture properties of rocks", in "Fracture Mechanics Methods for Ceramics, Rocks, and Concrete” (ASTM STP 745), ed. S.W. Freiman and E.R. Fuller Jr., pp. 185-195, publ. Philadelphia, American Society for Testing and Materials

7. More on rocks (and coal): Poland

J.R. Klepaczko, IPPT, Warsaw: 1980, Klepaczko, J. "Application of the split Hopkinson pressure bar to fracture dynamics" Inst. Phys. Conf. Ser. 47 201-214

1983, Klepaczko, J. "On the strain rate sensitivity of coal" Engng Trans. 31 (1983) 341-360

D. Kryszton & E. Stewarski, Institute of Mining and Geomechanics, Krakow, Rocks.

1986, Krzyszton, D., Mikos, T. and Stewarski, E. "Investigation of rock sample dynamic properties on the Hopkinson modified bar device" Arch. Mining Sci. 31 661-688

1987, Nelicki, A. "Some remarks on the limitations of the application of the method of split Hopkinson's pressure bar" Arch. Mining Sci. 32 109-121

Complete strain rate spectra for coal in compression; mean values of: σfm – maximum crushing stress; σf0 – crushing stress at strain of 1 %.

J. Klepaczko, Engng Trans. 31 (1983) 341-360

coal in Z direc,on

ε[s-1]

10-2 100 102 104

σf [MPa]

σf0(ε=0,01)

εmax[s-1]10-2 100 102 104

εf x10-3

coal in Z direc,on

Strain rate spectra for coal at fracturing strain: mean values of fm and f0. J. Klepaczko, Engng Trans. 31 (1983) 341-360

100 200 300

σmax[N/cm2] εmax[ / ]00 0

σmax(εmax)

εmax[s-1]

εmax(εmax)

Coal shale, Nowa Ruda, Poland. Krzyszton, D., Mikos, T. and Stewarski, E.

"Investigation of rock sample dynamic properties on the Hopkinson modified bar

device" Arch. Mining Sci. 31 (1986) 661-688

8. Surface temperature measurement techniques

8. RHA 10mm thick, 8 mm diameter, unlubricated, 32 m/s, 0.1ms interframe time

Dark blue implies T≥570K Straw colour implies T ca. 500K

S.M. Walley et al., J. Phys. IV France 134 (2006) 851-856

8. Tempering colour chart for steels

Turning tools

Hammers

Reamers

Swords

8. Infrared techniques

•  1984, Lataillade, J.L., Marchand, A. and Pouyet, J. "Testing of polycarbonate at high shear strain rates: Thermomechanical coupling", in "Proc. 9th Intl. Congress on Rheology (Advances in Rheology 3)", ed. B. Mena, A. Garcia-Rejon and C. Rangel-Nafaile, pp. 137-146, publ. Mexico City, National Autonomous University of Mexico

•  1995, Kruszka, L. and Nowacki, W.K. "Thermoplastic analysis of normal impact of long cylindrical specimen: Experiment and comparison with the numerical calculation" J. Thermal Stresses 18 313-334

•  1998, Macdougall, D.A.S. and Harding, J. "The measurement of specimen

surface temperature in high-speed tension and torsion tests" Int. J. Impact Engng 21 473-488

8. Infrared techniques

•  2000, Macdougall, D. "Determination of the plastic work converted to heat using radiometry" Exper. Mech. 40 298-306

•  2000, Walley, S.M., Proud, W.G., Rae, P.J. and Field, J.E. "Comparison of two

methods of measuring the rapid temperature rises in split Hopkinson bar specimens" Rev. Sci. Instrum. 71 1766-1771

•  2009, Guzmán, R., Mélendez, J., Aranda, J.M., Essa, Y.E., López, F. and Pérez-Castellanos, J.L. "Measurement of temperature increment in compressive quasistatic and dynamic tests using infrared thermography" Strain 45 179-189

8. France: IR measurement of temperature in dynamic torsion of polycarbonate (1984)

A. Marchand (1984) “Étude experimentale par barres de Hopkinson du comportement rhéologique de polymères solides à grande vitesse de distortion”,

PhD thesis, Univ. of Bordeaux I

8. Oxford: b as a function of torsional strain for Ti6Al4V (1998)

D. Macdougall & J. Harding, Int. J. Impact Engng 21 (1998) 473

8. Cambridge: IR Thermovision streak for iron (2000)

Walley, S.M., Proud, W.G., Rae, P.J. and Field, J.E. Rev. Sci. Instrum. 71 (2000) 1766-1771

8. Spain: IR temperature studies

Guzmán, R., Mélendez, J., Aranda, J.M., Essa, Y.E., López, F. and

Pérez-Castellanos, J.L. "Measurement of temperature

increment in compressive quasistatic and dynamic tests using infrared thermography" Strain 45 (2009)

179-189

Guzmán, R., Mélendez, J., Aranda, J.M., Essa, Y.E., López, F. and Pérez-Castellanos, J.L. "Measurement of temperature increment in compressive quasistatic and dynamic

tests using infrared thermography" Strain 45 (2009) 179-189

Guzmán, R., Mélendez, J., Aranda, J.M., Essa, Y.E., López, F. and Pérez-Castellanos, J.L. "Measurement of temperature increment in compressive quasistatic and dynamic

tests using infrared thermography" Strain 45 (2009) 179-189

8. Germany: IR studies of ASBs in a steel

Clos, R., Schreppel, U. and Veit, P. "Experimental investigation of adiabatic shear band formation in steels" J. Phys. IV France 10(Pr. 9) (2000) 257-262

8. Germany: IR studies of ASBs in a steel

Clos, R., Schreppel, U. and Veit, P. "Experimental investigation of adiabatic shear band formation in steels" J. Phys. IV France 10(Pr. 9) (2000) 257-262

9. Developments in Germany

9. German labs and researchers

•  Lothar Meyer, Fraunhofer IFAM, Bremen; Technical University Chemnitz (ASBs, machining, crash, history effects)

•  Essam El-Magd, RWTH Aachen (elastic-plastic waves, shear bands)

•  Stefan Hiermaier, Reinhard Tham, EMI Freiburg (low impedance materials, concrete)

•  Rainer Clos, Magdeburg (speckle, IR measurement of ASBs)

•  K. Stiebler, Fraunhofer IFAM Bremen (biaxial Hopkinson bar testing)

•  Jarzy Najar, Munich (spalling in ceramic bars)

•  Erhardt Lach, ISL Saint-Louis (metals, particle-reinforced metals)

9. Germany: Hat-shaped specimen for fracture and shear band studies

1981, Hartmann, K.-H., Kunze, H.-D. and Meyer, L.W. "Metallurgical effects on impact loaded materials", in "Shock Waves and High Strain rate Phenomena in Metals", ed. M.A. Meyers and L.E. Murr, pp. 325-337, publ. New York, Plenum

9. Germany: Indenter specimen for shear band studies

1986, Meyer, L.W. and Manwaring, S. "Critical adiabatic shear strength of low alloyed steel under compressive loading", in "Metallurgical Applications of Shock-Wave and High-Strain-Rate Phenomena", ed. L.E. Murr, K.P. Staudhammer and

M.A. Meyers, pp. 657-674, publ. New York, Marcel-Dekker

9. Germany: High rate biaxial testing

•  1989, Stiebler, K., Kunze, H.-D. and Staskewitsch, E. "Plastic flow of a ferritic mild steel and a high strength austenitic steel under dynamic biaxial loading" Inst. Phys. Conf. Ser. 102 181-188

•  1991, Stiebler, K., Kunze, H.D. and El Magd, E. "Description of the flow behavior of a high strength austenitic steel under biaxial loading by a constitutive equation" Nuclear Engng Des. 127 85-93

•  1992, Staskewitsch, E. and Stiebler, K. "Mechanical behavior of a high strength austenitic steel under dynamical biaxial loading", in "Shock-Wave and High-Strain-Rate Phenomena in Materials", ed. M.A. Meyers, L.E. Murr and K.P. Staudhammer, pp. 107-116, publ. New York, Marcel Dekker

Stiebler, K., Kunze, H.D. and El Magd, E. Nuclear Engng Des. 127 (1991) 85-93

Stiebler, K., Kunze, H.D. and El Magd, E.

Nuclear Engng Des. 127 (1991) 85-93

10. Developments in Russia (USSR)

10. USSR: Beginnings with G.V. Stepanov at Kiev

•  1974, Stepanov, G.V. "Effect of the loading scheme on extension and compression in high-speed tests" Strength Mater. 6 195-197

•  1974, Stepanov, G.V. "Analysis of the stress state of a specimen during high-speed testing in tension" Strength Mater. 6 1332-1335

•  1980, Stepanov, G.V. and Astanin, V.V. "High-speed impact compression testing of metals" Strength Mater. 12 210-213

10. Russia: Soil studies by Anatoly Bragov at Nizhny Novgorod

1996, Bragov, A.M., Grushevsky, G.M. and Lomunov, A.K., Exper. Mech. 36 237-242

10. Russia: Soil studies by Anatoly Bragov at Nizhny Novgorod

•  1995, Bragov, A.M., Gandurin, V.P., Grushevskii, G.M. and Lomunov, A.K. "New potentials of Kolsky's method for studying the dynamic properties of soft soils" J. Appl. Mech. Tech. Phys. 36 476-481

•  1996, Bragov, A.M., Grushevsky, G.M. and Lomunov, A.K. "Use of the Kolsky method for confined tests of soft soils" Exper. Mech. 36 237-242

10. Russia (with Poland) (2000s)

L. Kruszka (of Military University of Technology, Warsaw) built SHPB system with A. Bragov (Research Institute of Mechanics, Nizhny Novgorod, Russia) for study of dynamic properties of beams and plates.

11. Developments in France

11. First French labs to have SHPBs and early researchers 70’s- 80’s

•  CEA Bruyères le Chatel, Michel Stelly

•  ENSAM Bordeaux, Jean-Luc Lataillade

•  ETCA Arcueil, Jacques Clisson

•  ENSM Nantes, Chi-Yuen Chiem

•  IUT Nantes, Maurice Leroy

•  LPMM Metz, Janusz Klepaczko

•  ISL Saint-Louis, André Lichtenberger

•  Ecole Polytechnique, Gérard Gary

11. French labs presently having SHPBs

•  Bretagne Sud University

•  CEA Valduc

•  Ecole Centrale de Nantes

•  Ecole Polytechnique

•  ENSAM Bordeaux

•  ENSI Bourges

•  ENSTA Brest

•  IMFS Strasbourg

•  INSA Rennes

•  ISL Saint Louis

•  LMT Cachan

•  LPMM Metz

•  NEXTER Bourges

•  Valenciennes University

11. France: Ceramics (alumina)

El Bounia, N.E., Robert-Arnouil, J.P., Gillaizeau, F. and Lataillade, J.L., 1988, “Thermomechanical characterization of engineering ceramics under dynamic

loading”, in “Impact Loading and Dynamic Behaviour of Materials”, ed. C.Y. Chiem, H.-

D. Kunze and L.W. Meyer, pp. 631-638, (Oberursel, Germany, DGM

Informationsgesellschaft mbH)

11. France

•  1980, C. Signoret, J.M. Pouyet, J-L. Lataillade, “Adaptation of a microcomputer system to a modified SHPB”, J. Phys. E: Sci. Instrum. 13 1284-1286

•  1984, J-L. Lataillade, A. Marchand, J. Pouyet, “Testing of polycarbonate at high shear strain rates: Thermomechanical coupling”, in “Proc. 9th Intl. Congress on Rheology (Advances in Rheology 3)”, pp. 137-146, publ. National Autonomous University of Mexico

11. France: First reported use of microcomputer with SHPB

11. France: Tensile momentum trapping to study damage in composites

•  1996, J-L. Lataillade, M. Delaet, F. Collombet, C. Wolff, “Effects of the intralaminar shear loading rate on the damage of multi-ply composites”, Int. J. Impact Engng 18 679-699

11. France: Momentum trapping in tensile SHPB

J-L. Lataillade, M. Delaet, F. Collombet, C. Wolff (1996) Int. J. Impact Engng 18 679-699

11. France: Effect of deformation rate on gas flow in polymer foam

11. France: Hat specimen for testing sheet steel

P. Mouro, G. Gary, H. Zhao, J. Phys. IV France 10(Pr.9) (2000) 149-154

11. France: Bulge specimen for testing sheet metal

V. Grolleau et al., DYMAT 2009 597-602

11. France: M-shaped specimen for applying tension in compression SHPB

D. Mohr & G. Gary, Exper. Mech. 47 (2007) 681-692

11. France: M-shaped specimen for applying tension in compression SHPB

D. Mohr & G. Gary, Exper. Mech. 47 (2007) 681-692

12. Summary

Many innovations in the Hopkinson bar technique have taken place in Europe.

Hopkinson bars continue to be developed, particularly in the areas of complex modes of loading (sheet metals), biaxial loading, large specimens, very high rates of strain (approaching shock), soft materials.

A history of Hopkinson bars in Europe

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