scholarly journals Dynamic properties of stainless steel under direct tension loading using a simple gas gun

2018 ◽  
Vol 183 ◽  
pp. 02035 ◽  
Author(s):  
Anatoly Bragov ◽  
Alexander Konstantinov ◽  
Leopold Kruszka ◽  
Andrey Lomunov ◽  
Andrey Filippov
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Tensile Load ◽  
Hopkinson Pressure Bar ◽  
Direct Tension ◽  
Stress Strain ◽  
Gas Gun

The combined experimental and theoretical approach was applied to the study of high-speed deformation and fracture of the 1810 stainless steel. The material tests were performed using a split Hopkinson pressure bar to determine dynamic stress-strain curves, strain rate histories, plastic properties and fracture in the strain rate range of 102 ÷ 104 s-1. A scheme has been realized for obtaining a direct tensile load in the SHPB, using a tubular striker and a gas gun of a simple design. The parameters of the Johnson-Cook material model were identified using the experimental results obtained. Using a series of verification experiments under various types of stress-strain state, the degree of reliability of the identified mathematical model of the behavior of the material studied was determined.

One-Dimensional Dynamic Compressive Behavior of EPDM Rubber

2003 ◽  
Vol 125 (3) ◽  
pp. 294-301 ◽  
Author(s):  
B. Song ◽  
W. Chen
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Dynamic Stress ◽  
Split Hopkinson Pressure Bar ◽  
Constant Strain Rate ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Epdm Rubber ◽  
One Dimensional

Dynamic compressive stress-strain curves at various strain rates of an Ethylene-Propylene-Diene Monomer Copolymer (EPDM) rubber have been determined with a modified split Hopkinson pressure bar (SHPB). The use of a pulse-shaping technique ensures that the specimen deforms at a nearly constant strain rate under dynamically equilibrated stress. The validity of the experiments was monitored by a high-speed digital camera for specimen edge deformation, and by piezoelectric force transducers for dynamic stress equilibrium. The resulting dynamic stress-strain curves for the EPDM indicate that the material is sensitive to strain rates and that the strain-rate sensitivity depends on the value of strain. Based on a strain energy function theory, a one-dimensional dynamic constitutive equation for this rubber was modified to describe the high strain-rate experimental results within the ranges of strain and strain rates presented in this paper.

Dynamic Mechanical Behavior of Two Fiber-Reinforced Composites

2012 ◽  
Vol 525-526 ◽  
pp. 261-264
Author(s):  
Y.Z. Guo ◽  
X. Chen ◽  
Xi Yun Wang ◽  
S.G. Tan ◽  
Z. Zeng ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Rate Dependent ◽  
Dynamic Loadings ◽  
Axial Splitting

The mechanical behavior of two composites, i.e., CF3031/QY8911 (CQ, hereafter in this paper) and EW100A/BA9916 (EB, hereafter in this paper), under dynamic loadings were carefully studied by using split Hopkinson pressure bar (SHPB) system. The results show that compressive strength of CQ increases with increasing strain-rates, while for EB the compressive strength at strain-rate 1500/s is lower then that at 800/s or 400/s. More interestingly, most of the stress strain curves of both of the two composites are not monotonous but exhibit double-peak shape. To identify this unusual phenominon, a high speed photographic system is introduced. The deformation as well as fracture characteristics of the composites under dynamic loadings were captured. The photoes indicate that two different failure mechanisms work during dynamic fracture process. The first one is axial splitting between the fiber and the matrix and the second one is overall shear. The interficial strength between the fiber and matrix, which is also strain rate dependent, determines the fracture modes and the shape of the stress/strain curves.

Numerical Simulation of SHPB Test for Concrete under Confining Pressure

2014 ◽  
Vol 580-583 ◽  
pp. 3144-3148 ◽  
Author(s):  
Hua Zhang ◽  
Ao Yu Xie ◽  
Yu Wei Gao
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Confining Pressure ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Confining Pressures ◽  
Stress States ◽  
Pressure Bar ◽  
The Impact

Using the HJC dynamic constitutive model, the Split Hopkinson Pressure Bar (SHPB) impact test with confining pressure for concrete was simulated in the software ANSYS/LS-DYNA. The confining pressure was simulated by applying constant pressure around the specimen. The triangle velocity wave, which has less diffusion, is used as loader in the simulation. The confining pressures used were 0MPa, 2MPa, 4MPa, 8MPa and 16MPa and the stress-strain curves were presented. The influence of confining pressure on the dynamic properties was analyzed by comparing the stress-strain curves of concrete under different stress states. The strain rate decreases sensitively as long as the confining pressure increases. By debugging the impact velocity, the stress-strain curves under the similar strain rate were obtained, which indicate the toughening and reinforcing effect with the increase of confining pressure.

scholarly journals Study on the dynamic properties of AM-SLM AlSi10Mg alloy using the Split Hopkinson Pressure Bar (SHPB) technique

2018 ◽  
Vol 183 ◽  
pp. 04005 ◽  
Author(s):  
Bar Nurel ◽  
Moshe Nahmany ◽  
Adin Stern ◽  
Nahum Frage ◽  
Oren Sadot
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Static Mechanical ◽  
Split Hopkinson ◽  
Pressure Bar

Additive manufacturing by Selective Laser Melting of metals is attracting substantial attention, due to its advantages, such as short-time production of customized structures. This technique is useful for building complex components using a metallic pre-alloyed powder. One of the most used materials in AMSLM is AlSi10Mg powder. Additively manufactured AlSi10Mg may be used as a structural material and it static mechanical properties were widely investigated. Properties in the strain rates of 5×102–1.6×103 s-1 and at higher strain rates of 5×103 –105 s-1 have been also reported. The aim of this study is investigation of dynamic properties in the 7×102–8×103 s-1 strain rate range, using the split Hopkinson pressure bar technique. It was found that the dynamic properties at strain-rates of 1×103–3×103 s-1 depend on a build direction and affected by heat treatment. At higher and lower strain-rates the effect of build direction is limited. The anisotropic nature of the material was determined by the ellipticity of samples after the SHPB test. No strain rate sensitivity was observed.

scholarly journals High strain rate behaviour of fiber reinforced concrete

2018 ◽  
Vol 183 ◽  
pp. 02012
Author(s):  
Miloslav Popovič ◽  
Jaroslav Buchar ◽  
Martina Drdlová
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Fiber Reinforced Concrete ◽  
Hopkinson Pressure Bar ◽  
Static Test ◽  
Pressure Bar

The results of dynamic compression and tensile-splitting tests of concrete reinforced by randomly distributed short non – metallic fibres are presented. A Split Hopkinson Pressure Bar combined with a high-speed photographic system, was used to conduct dynamic Brazilian tests. Quasi static test show that the reinforcement of concrete by the non-metallic fibres leads to the improvement of mechanical properties at quasi static loading. This phenomenon was not observed at the high strain rate loading .Some explanation of this result is briefly outlined.

scholarly journals Dynamic Constitutive Model of Ultra-High Molecular Weight Polyethylene (UHMWPE): Considering the Temperature and Strain Rate Effects

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1561 ◽  
Author(s):  
Kebin Zhang ◽  
Wenbin Li ◽  
Yu Zheng ◽  
Wenjin Yao ◽  
Changfang Zhao
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Plastic Material ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Ballistic Performance ◽  
Stress Strain ◽  
Different Temperatures

The temperature and strain rate significantly affect the ballistic performance of UHMWPE, but the deformation of UHMWPE under thermo-mechanical coupling has been rarely studied. To investigate the influences of the temperature and the strain rate on the mechanical properties of UHMWPE, a Split Hopkinson Pressure Bar (SHPB) apparatus was used to conduct uniaxial compression experiments on UHMWPE. The stress–strain curves of UHMWPE were obtained at temperatures of 20–100 °C and strain rates of 1300–4300 s−1. Based on the experimental results, the UHMWPE belongs to viscoelastic–plastic material, and a hardening effect occurs once UHMWPE enters the plastic zone. By comparing the stress–strain curves at different temperatures and strain rates, it was found that UHMWPE exhibits strain rate strengthening and temperature softening effects. By modifying the Sherwood–Frost model, a constitutive model was established to describe the dynamic mechanical properties of UHMWPE at different temperatures. The results calculated using the constitutive model were in good agreement with the experimental data. This study provides a reference for the design of UHMWPE as a ballistic-resistant material.

An improved method for compressive stress-strain measurements at very high strain rates

1992 ◽  
Vol 438 (1902) ◽  
pp. 153-170 ◽  
Keyword(s):  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Pure Copper ◽  
High Strength ◽  
Tungsten Alloy ◽  
High Speed Photography ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

This paper describes a modification of the split Hopkinson pressure bar, to allow compression testing of high strength metals at a strain rate of up to about 10 5 s –1 . All dimensions are minimized to reduce effects of dispersion and inertia, with specimens of the order of 1 mm diameter. Strain is calculated from the stress record and calibrated with high-speed photography. Particular attention has been paid to the accuracy of the technique, and errors arising from nonlinearity in the instrumentation, dispersion, frictional restraint and inertia have all been quantitatively assessed. Stress–strain results are presented of Ti 6A14V alloy, a high strength tungsten alloy, and pure copper.

High strain-rate behavior of natural fiber-reinforced polymer composites

2011 ◽  
Vol 46 (9) ◽  
pp. 1051-1065 ◽  
Author(s):  
Wonsuk Kim ◽  
Alan Argento ◽  
Ellen Lee ◽  
Cynthia Flanigan ◽  
Daniel Houston ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
High Strain Rate ◽  
Strain Rate ◽  
Polymer Composites ◽  
Natural Fiber ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Natural Fibers ◽  
Hopkinson Pressure Bar ◽  
Stress Strain

The high strain-rate constitutive behavior of polymer composites with various natural fibers is studied. Hemp, hemp/glass hybrid, cellulose, and wheat straw-reinforced polymeric composites have been manufactured, and a split-Hopkinson pressure bar apparatus has been designed to measure the dynamic stress–strain response of the materials. Using the apparatus, compressive stress–strain curves have been obtained that reveal the materials’ constitutive characteristics at strain rates between 600 and 2400 strain/s. Primary findings indicate that natural fibers in thermoset composites dissipate energy at lower levels of stress and higher strain than glass-reinforced composites. In the case of thermoplastic matrices, the effect on energy dissipation of natural fibers vs. conventional talc reinforcements is highly dependent on resin properties. Natural fibers in polypropylene homopolymer show improved reinforcement but have degraded energy dissipation compared to talc. Whereas in polypropylene copolymer, natural fibers result in improved energy dissipation compared to talc. These data are useful for proper design, analysis, and simulation of lightweight biocomposites.

High Strain Rate and High Temperature Behavior of Ti–6Al–4V Alloy Under Compressive Loading

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Nitin B. Bhalerao ◽  
Suhas S. Joshi ◽  
N. K. Naik
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Equilibrium ◽  
Dynamic Properties ◽  
Weight Ratio ◽  
High Rate ◽  
Material Strength ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Two Phase

The titanium alloy (grade 5) is a two-phase material, which finds significant applications in aerospace, medical, marine fields, owing to its superior characteristics like high strength-to-weight ratio, excellent corrosion resistance, and good formability. Hence, the dynamic characteristics of the Ti-6Al-4V alloy are an important area to study. A compressive split Hopkinson pressure bar (SHPB) was used to evaluate the dynamic properties of Ti-6Al-4V alloy under various strain rates between 997 and 1898s−1, and at temperatures between −10 °C and 320 °C. It was evident that the material strength is sensitive to both strain rate and temperature; however, the latter is more predominant than the former. The microstructure of the deformed samples was examined using electron back-scattered diffraction (EBSD). The microscopic observations show that the dynamic impact characteristics of the alloy are higher at higher strain rates than at quasi-static strain rates. The SHPB tests show that the force on the transmitter bar is lower than the force on the incident bar. This indicates that the dynamic equilibrium cannot be achieved during high rate of damage evolution. Various constants in Johnson–Cook (JC) model were evaluated to validate the results. An uncertainty analysis for the experimental results has also been presented.

Measurement of Mechanical Properties of St 37 Material at High Strain Rates Using a Split Hopkinson Pressure Bar

2014 ◽  
Vol 660 ◽  
pp. 562-566 ◽  
Author(s):  
Akbar Afdhal ◽  
Leonardo Gunawan ◽  
Sigit P. Santosa ◽  
Ichsan Setya Putra ◽  
Hoon Huh
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Test Specimen ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Split Hopkinson ◽  
Pressure Bar

The dynamic mechanical properties of a material are important keys to investigate the impact characteristic of a structure such as a crash box. For some materials, the stress-strain relationships at high strain rate loadings are different than that at the static condition. These mechanical properties depend on the strain rate of the loadings, and hence an appropriate testing technique is required to measure them. To measure the mechanical properties of a material at high strain rates, ranging from 500 s-1 to 10000 s-1, a Split Hopkinson Pressure Bar is commonly used. In the measurements, strain pulses are generated in the bars system, and pulses being reflected and transmitted by a test specimen in the bar system are measured. The stress-strain curves as the material properties of the test specimen are obtained by processing the measured reflected and transmitted pulses. This paper presents the measurements of the mechanical properties of St 37 mild steel at several strain rates using a Split Hopkinson Pressure Bar. The stress-strain curves obtained in the measurement were curve fitted using the Power Law. The results show that the strength of St 37 material increases as the strain rate increases.

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