Experimental Work for Bar Straightness Effect Evaluation of Split Hopkinson Pressure Bar

Afdhal, Afdhal; Gunawan, Leonardo; Dirgantara, Tatacipta

doi:10.5614/j.eng.technol.sci.2021.53.6.13

Cited by 2 publications

(3 citation statements)

References 33 publications

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“…Meanwhile, the remaining compression pulse will be transmitted to the specimen and deforms it before transmitted to the transmitter bar. This transmitted pulse then will also be recorded by the strain gauge when reaching the middle of the transmitter bar [30]. Typical pulses produced by SHPB testing are shown in Figure 6.…”

Section: High Strain Rate Test Using Split Hopkinson Pressure Bar (Shpb)mentioning

confidence: 99%

Mechanical Anisotropy of Cold-Rolled St-37 Steel Plate Under High Strain Rates Loadings

Perkasa

Gunawan

Santosa

et al. 2023

MECHTA

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Cold rolling process in metal could increase its strength and hardness, but also induces mechanical anisotropy. This is caused by unresolved plastic strain and microstructural changes caused by plastic deformation exerted by pair of rolls at a relatively low temperature. This research aims to provide understandings on anisotropic and strain rate sensitive behaviour of St-37 mild steel. The microstructure of rolled and unrolled St-37 plate were observed in 3 directions relative to the rolling direction. The cylindrical specimens were then prepared from rolled plate with 33.3% reduction in the orientation of 0o, 45o, and 90o relative to the rolling direction. Specimens were also prepared from unrolled plate as comparison in the same directions. These specimens were then tested in compression loading, first in quasi-static condition, and then by using Split-Hopkinson Pressure Bar (SHPB) at the strain rate of 1200 s-1. The experimental results in the form of stress-strain curves are used to obtain the parameters of Simplified Johnson-Cook viscoplastic model. The anisotropy of yield strength in rolled specimens could be seen on both quasi-static and high strain rate condition, where the highest strength found on the specimens perpendicular to the rolling direction. In addition, the effect of cold rolling to the strain rate sensitivity of the material were also captured successfully in this study, where specimens from rolled plate show less strain rate sensitivity compared to the unrolled specimens.

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Section: High Strain Rate Test Using Split Hopkinson Pressure Bar (Shpb)mentioning

confidence: 99%

Mechanical Anisotropy of Cold-Rolled St-37 Steel Plate Under High Strain Rates Loadings

Perkasa

Gunawan

Santosa

et al. 2023

MECHTA

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show abstract

“…This approach has been utilized by Vedantam et al (2005). Others (Afdhal et al (2014); Afdhal et al (2016); Leonardo et al (2013)) have determined it by curve fitting. Here we are finding the constant A by plotting the graph of the ln(strain rate ) vs Yield stress and finding out the Y intercept of the linear fit.…”

Section: Determination Of Constant a And The Selection Of The Strain ...mentioning

confidence: 99%

“…They have not got a unified model but modelled, each curve individually using the power law model. Afdhal et al (2016) 2 Experimental Method…”

Section: Introductionmentioning

confidence: 99%

Determining the Intermediate and High Strain Rate Properties of Bar Bending Braking System Material in a Forward Velocity Sled

Sriniva,

Vorkady

et al. 2023

Preprint

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The Bar Bending Braking System (BBBS) in a forward velocity sled utilizes the plastic deformation of the metallic bars to dissipate the Kinetic energy of impact and generate the required deceleration pulse. The National Aerospace Laboratories forward velocity sled’s BBBS material, Mild steel St37-2, is characterized in compression at room temperature, using the quasi-static tests and the Split Hopkinson Pressure Bar (SHPB) at strain rates ranging from 10− 3/s − 2500/s. Very high strain rate dependence of yield and flow stress was observed from these tests as there was nearly a 100% increase in the yield stress between the highest and lowest strain rates. Thinner samples (L/D < 0.5) were used for the SHPB tests apart from the usual ratio (L/D = 0.5) samples and it was observed that the stress strain curves of these thinner samples were consistent with those of the samples with L/D = 0.5 showing that there was no significant effect of the three-dimensional state of stress on the curves. The Compression stress-strain data for the steel, which has over 12 stress strain curves at different strain rates, is analysed to determine the Viscoplastic Johnson-Cook (JC) model and the Cowper-Symonds (CS) Model. The JC Model was developed over a limited strain rate range (0.001-300/s), as linear dependence of the log(strainrate) to the yield or flow stress was only possible in this range. The CS model was developed for the entire range and effectively models the stress strain curves throughout the range of strain rate. The values of the JC and CS constants are compared with existing literature for St 37 steel and are found similar for strain rate sensitivity though there is considerable difference in the static plasticity constants.

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Experimental Work for Bar Straightness Effect Evaluation of Split Hopkinson Pressure Bar

Cited by 2 publications

References 33 publications

Mechanical Anisotropy of Cold-Rolled St-37 Steel Plate Under High Strain Rates Loadings

Mechanical Anisotropy of Cold-Rolled St-37 Steel Plate Under High Strain Rates Loadings

Determining the Intermediate and High Strain Rate Properties of Bar Bending Braking System Material in a Forward Velocity Sled

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