A tension split Hopkinson bar for investigating the dynamic behavior of sheet metals

Huh, Hoon; Kang, Woo-Jong; Han, Seung Baik

doi:10.1007/bf02411046

Cited by 126 publications

(41 citation statements)

References 12 publications

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“…Some experimental techniques also allow direct impact tension to be performed [14,25,26,31,32,38]. In conclusion, the result of using different geometries for the same type of equipment will be that some differences may appear due only to specimen dimensions [25,37].…”

Section: Remarks On Experimental Set-ups For Dynamic Tension Tests Smentioning

confidence: 99%

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

et al. 2005

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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 spec imen lengths from 10 to 40 mm submitted to impact velocities ranging from 10 to 100 m/s.Keywords: Constitutive relation; Dynamic tension; Normalization; Plastic instability; Numerical simulations Thermoviscoplastic modelingTo study the dynamic processes of plastic deformation in sheet metals, a well defined constitutive relation has earlier been proposed. Several processes of fast deformation have been previously studied by applying that relation: perforation [1], double shear by direct impact [2], the Taylor test and fast tension test [3]. With the constitutive relation, Eq. (1), the effect of temperature and strain rate on the flow stress can be studied and analyzed. It is clear that the adiabatic increase of temperature has a substantial effect on the flow stress and it induces a decrease in the ultimate tensile stress. In order to describe precisely the behavior of materials at high strain rates and temperatures, the equivalent stress r needs to be taken as the sum of two components r l and r * which are, respectively, the internal and the effective stress. The first component is directly related to the strain hardening of the material and the second defines the contribution due to the thermal activation (a combination of temperature and strain rate). The constitutive relation can be written in terms of equivalent scalar quantities:where e p is the equivalent plastic strain, T is the absolute temperature, E 0 is the YoungÕs modulus at T 0 K and E(T) is the evolution of the modulus as a function of temperature. Eq. (1) is based to some extent on physical considerations [2]. The explicit expressions for both stress components are given below:where Bð _ e p ; T Þ and nð _ e p ; T Þ are the modulus of plasticity and the strain hardening exponent, respectively. These quantities, defined by Eqs. (3) and (5), respectively, take into account the experimental observations that the strain hardening itself depends on temperature and strain rate.

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Section: Remarks On Experimental Set-ups For Dynamic Tension Tests Smentioning

confidence: 99%

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

et al. 2005

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“…Recently, this loading method has become more and more desirable because it allows the optical access to the specimen surface, facilitating the application of high speed imaging to tensile tests. One of the most popular version for tensile tests, commonly named split Hopkinson tension bar (SHTB), consists in a tube-like impactor that is placed around the input bar and is accelerated by compressed air towards an anvil at the outer end of the input bar [9][10][11][12][13][14]. Hence, a tensile wave is generated and propagates along the input bar towards the specimen.…”

Section: Introductionmentioning

confidence: 99%

Design of an Innovative System for Wave Generation in Direct Tension–Compression Split Hopkinson Bar

Mancini

Sasso

Rossi

et al. 2015

J. dynamic behavior mater.

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The split Hopkinson bar is a well-known apparatus for performing tests at high strain-rate on engineering materials. The specimen is placed between two long bars and quickly loaded by a pressure wave, which travels at sound speed along the input bar, passes through the specimen, then is partly reflected and partly transmitted to the output bar. In the classical version, the input wave is generated by the impact of a striker bar against the input bar at a given velocity. In the direct version of the Hopkinson bar, the wave is generated by pre-loading and releasing a portion of the input bar. However, with this approach the rise time of the pressure wave is usually longer respect to the classical version. In this paper, an innovative wave generation system is presented, which exploits the abrupt shear fracture of a thin brittle disc. In this way, the rise time of the incident waves can be close to that obtained by the classical impact-based Hopkison bars (80 ls instead of 50 ls). Moreover, both tension and compression tests can be carried out with the same experimental system.

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“…During passage of reflected tensile wave generated a tension in the specimen; the collar was inactive this time. In this case, wave distortion occurred due to the clearance of the threaded region [19]. Huh et al [19] developed a tensile split Hopkinson pressure bar (SHPB) in which a hollow striker tube is fired from gas gun and impacts an anvil which is a part of the incident bar.…”

Section: Introductionmentioning

confidence: 99%

“…In this case, wave distortion occurred due to the clearance of the threaded region [19]. Huh et al [19] developed a tensile split Hopkinson pressure bar (SHPB) in which a hollow striker tube is fired from gas gun and impacts an anvil which is a part of the incident bar. At the impact, a tensile pulse is generated in incident bar and propagates through the specimen to the transmitted bar.…”

Section: Introductionmentioning

confidence: 99%

“…The present investigation was made to address this void. The dynamic experiments were performed by using modified tensile split Hopkinson pressure bar, using a combination of Nicholas [17,18] and Huh et al [19] techniques, to investigate the strain-rate sensitivity of AA5182 and AL6111-T4, during tensile loading, including welded alloy as well. The KHL constitutive model was used to correlate and predict the experimental response.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Manufacturing Processes and Welding Type on Quasi-static and Dynamic Responses of Aluminum Alloys: Experiments and Modeling

Baig

Khan

Choi

et al. 2015

J. dynamic behavior mater.

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Measured responses of two aluminum alloys over a wide range of strain-rates (10 -5 to 10 3 s -1 ) and temperatures are presented. The aluminum alloys include AA5182-O and AL6111-T4. A tensile spilt Hopkinson pressure bar was used for the dynamic experiments. The aluminum AA5182-O alloy (manufactured using continuous casting and direct chilling processes) including its first and second generation gas tungsten arc welded and friction stir welded TWB's exhibited negative strain-rate sensitivity. AL6111-T4 is found to have positive strain-rate sensitivity. The Khan-Huang-Liang constitutive model is shown to correlate and predict the observed responses reasonably well. The texture evolution of the AA5182-O and AL6111-T4 sheets during uniaxial tension is investigated using the EBSD technique and full-constraint polycrystal model. It is observed through the EBSD analysis that, the stable orientation is strongly dependent on the initial texture components.Keywords AA5182-O Á AL6111-T4 Á Quasi-static and dynamic response Á Tensile split Hopkinson bar Á EBSD

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A tension split Hopkinson bar for investigating the dynamic behavior of sheet metals

Cited by 126 publications

References 12 publications

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

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

Design of an Innovative System for Wave Generation in Direct Tension–Compression Split Hopkinson Bar

Effect of Manufacturing Processes and Welding Type on Quasi-static and Dynamic Responses of Aluminum Alloys: Experiments and Modeling

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