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 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.

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.

Impact Compressive Properties of Foamed Film with Closed Cell

2014 ◽  
Vol 566 ◽  
pp. 134-139 ◽  
Author(s):  
Hiroyuki Yamada ◽  
Ryo Okui ◽  
Nagahisa Ogasawara ◽  
Hidetoshi Kobayashi ◽  
Kinya Ogawa
Keyword(s):  
Strain Rate ◽  
Impact Test ◽  
Split Hopkinson Pressure Bar ◽  
Rate Dependency ◽  
Hopkinson Pressure Bar ◽  
Compressive Properties ◽  
Static Test ◽  
Closed Cell ◽  
Pressure Bar ◽  
The Impact

The compressive properties of foamed polyethylene (PE) film with a closed cell for electronic devices have been investigated. A commercial closed cell foamed PE film with a density of 330 kg/m3 was used. Quasi-static testing was carried out at strain rates of 10−3 to 10−1 s−1. The strain rate of the impact test was approximately 105 s−1 by means of split Hopkinson pressure bar method. Within the set of experiments, the compressive stress increased with the strain rate in both the quasi-static and impact test. In particular, the flow stress increased substantially with the increasing strain rate in the impact deformation. At strains of less than 0.4, the trapped air was locally compressed within the cells, which led to the strain rate dependency of strength in the quasi-static test and the impact test.

scholarly journals Determination of the high-strain rate elastic modulus of printing resins using two different split Hopkinson pressure bars

2021 ◽  
Author(s):  
S. Aghayan ◽  
S. Bieler ◽  
K. Weinberg
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Strain Rate Loading

AbstractThe usage of resin-based materials for 3D printing applications has been growing over the past decades. In this study, two types of resins, namely a MMA-based resin and an ABS-based tough resin, are subjected to compression tests on a split Hopkinson pressure bar to deduce their dynamic properties under high strain rate loading.Two Hopkinson bar setups are used, the first one is equipped with aluminum bars and the second one with PMMA bars. From the measured strain waves, elastic moduli at high strain rates are derived. Both setups lead to values of $E=3.4$ E = 3.4 –3.8 GPa at a strain rate of about 250 s−1. Numerical simulations support the experiments. Moreover, considering the waves gained from the two different bar setups, PMMA bars appear to be well-suited for testing resin samples and are therefore recommended for such applications.

Dynamic Stress-Strain Behavior of AZ91 Alloy at High-Strain Rate

2007 ◽  
Vol 546-549 ◽  
pp. 89-92 ◽  
Author(s):  
Gui Ying Sha ◽  
En Hou Han ◽  
Yong Bo Xu ◽  
Lu Liu
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Dynamic Stress ◽  
Split Hopkinson Pressure Bar ◽  
Az91 Alloy ◽  
Hopkinson Pressure Bar ◽  
Stress Strain ◽  
Strain Rate Effects ◽  
Strain Behavior ◽  
Pressure Bar

The dynamic stress-strain behavior of the AZ91 alloys in different treatment conditions (as-cast, T4 and T6) was investigated by means of split Hopkinson pressure bar. It was found that the flow stress increased at first, and then declined with the strain rate increasing at the range of 102~103s-1 for the alloys in these three conditions. And the alloys exhibited both positive and negative strain rate effects. The former was caused by strain rate strengthening and the latter was caused by strain rate weakening. However the flow stress for the alloy in aged condition at the same strain rate was higher than both of the alloys in as-cast and solution conditions. The study also showed that the maximum strains of the alloys in different conditions increased with the strain rate increasing, and the strain rate to fracture for the alloy in solution condition was higher than those of other two alloys. The work-hardening of α–Mg matrix and the reinforcement of β-Mg17Al12 phases led to the strengthening of the alloy, while thermal softening of matrix, the fracture of β phases and initiation and propagation of the cracks were responsible for the weakening of the alloy.

scholarly journals Dynamic Compressive Characteristics of Sandstone under Confining Pressure and Radial Gradient Stress with the SHPB Test

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Shiming Wang ◽  
Yunsi Liu ◽  
Jian Zhou ◽  
Qiuhong Wu ◽  
Shuyi Ma ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Large Diameter ◽  
Dynamic Strength ◽  
Confining Pressure ◽  
Peak Strain ◽  
Hopkinson Pressure Bar ◽  
Radial Gradient ◽  
The Impact

Research on the dynamic compressive characteristics of sandstone under radial gradient stress and confining pressure is conducive to understanding the characteristics of the surrounding rock, especially in an excavation operation for an underground mine roadway and tunnel. The present work aimed at studying the effects of radial gradient stress and confining pressure on the impact of compression of sandstone using a large-diameter split Hopkinson pressure bar. The results showed that the dynamic strength of sandstone under radial gradient stress increased with strain rate following a power function, and the dynamic strength of the sandstone under radial gradient stress was lower and more sensitive to strain rate. The increase in strain at peak stress (peak strain) was linearly correlated with the strain rate under different confining pressures. The sensitivity of the peak strain to confining pressure was lower for the sandstone with a hole, while the values of the elastic modulus were decreased. However, further increasing the stain rate would lead to an increase in the elastic modulus. Also, the ductility of the sandstone with a hole tested in this study was found to improve more significantly. Finally, with an increase in the incident energy, the absorbed energy per unit volume would increase, but would not be affected obviously by the radial gradient stress.

scholarly journals A Comparative Study on Rock Properties in Splitting and Compressive Dynamic Tests

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Nan Wu ◽  
Zhende Zhu ◽  
Yaojun Zhou ◽  
Shihu Gao
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Tensile Tests ◽  
Rock Properties ◽  
Hopkinson Pressure Bar ◽  
Rock Samples ◽  
Dimensionless Stress ◽  
Split Hopkinson ◽  
Pressure Bar

The dynamic properties of rock in splitting (tensile) and compressive tests are the focus of rock dynamic mechanics research. In this study, a split Hopkinson pressure bar (SHPB) apparatus was used to assess the comparability and strain rate effect of rock samples under two kinds of load conditions. With an increase in impact velocity under compression and splitting (tensile) tests, the strain rate of the samples increased continuously. The rock properties and strain rate in the two kinds of samples exhibited clear similarities: the dimensionless stress-strain curves of the rock samples were similar under the same strain rates. The peak strength and elastic modulus of the two kinds of samples increased with an increase in the strain rate. The number of cracks increased from intergranular to transgranular failure. The rack initiation value of the two kinds of samples was close at the same strain rate and declined with an increase in the strain rate as evidenced by a power function.

Study on Dynamic Behavior of AFRP-Wrapped Circular Concrete Specimens under Repeated Impacts

2017 ◽  
Vol 25 (1) ◽  
pp. 103-112
Author(s):  
Hengwen Song ◽  
Hui Yang ◽  
Shi Zhang
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Impact Damage ◽  
Peak Stress ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Repeated Impacts ◽  
Damage Condition ◽  
Pressure Bar ◽  
The Impact

A series of damage tests and axially repeated compressive tests with high strain rates were conducted to investigate the behavior of aramid fiber reinforced polymer (AFRP) wrapped concrete under repeated impacts. The relation between damage condition and variables such as impact number and polymer thickness were examined. The tests were performed using a 100 mm diameter Split Hopkinson Pressure Bar (SHPB) apparatus and a nonmetal supersonic test meter. Various AFRP layers were applied to produce varied confinement ratios. The experimental results indicated that the AFRP-wrapped concrete exhibited excellent performance in resisting repeated impacts. Also, the specimens maintained their shapes and bearing capacity after multiple impacts with a mean strain rate of 50 s−1. No distinct decline was observed from the history of peak stress and impact toughness in AFRP-wrapped concrete. Moreover, additional AFRP layers significantly decreased the impact damage on the core concrete, as reflected by the different strain rate histories in damage progression.

scholarly journals Impact Behavior of Recycled Aggregate Concrete Based on Split Hopkinson Pressure Bar Tests

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yubin Lu ◽  
Xing Chen ◽  
Xiao Teng ◽  
Shu Zhang
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Impact Behavior ◽  
Hopkinson Pressure Bar ◽  
Aggregate Concrete ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
The Impact

This paper presents the experimental results of recycled aggregate concrete (RAC) specimens prepared with five different amounts of recycled coarse aggregate (RCA) (i.e., 0, 25%, 50%, 75%, and 100%) subjected to impact loading based on split Hopkinson pressure bar tests. Strain-rate effects on dynamic compressive strength and critical strain of RAC were studied. Results show that the impact properties of RAC exhibit strong strain-rate dependency and increase approximately linearly with strain-rate. The transition point from low strain-rate sensitivity to high sensitivity decreases with the increase of matrix strength.

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