scholarly journals Experimental and Numerical Evaluation of Rock Dynamic Test with Split-Hopkinson Pressure Bar

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Kang Peng ◽  
Ke Gao ◽  
Jian Liu ◽  
Yujiao Liu ◽  
Zhenyu Zhang ◽  
...  

Feasibility of rock dynamic properties by split-Hopkinson pressure bar (SHPB) was experimentally and numerically evaluated with ANSYS/LS-DYNA. The effects of different diameters, different loading rates, and different propagation distances on wave dispersion of input bars in SHPB with rectangle and half-sine wave loadings were analyzed. The results show that the dispersion effect on the diameter of input bar, loading rate, and propagation distance under half-sine waveform loading is ignorable compared with the rectangle wave loading. Moreover, the degrees of stress uniformity under rectangle and half-sine input wave loadings are compared in SHPB tests, and the time required for stress uniformity is calculated under different above-mentioned loadings. It is confirmed that the stress uniformity can be realized more easily using the half-sine pulse loading compared to the rectangle pulse loading, and this has significant advantages in the dynamic test of rock-like materials. Finally, the Holmquist-Johnson-Concrete constitutive model is introduced to simulate the failure mechanism and failure and fragmentation characteristics of rock under different strain rates. And the numerical results agree with that obtained from the experiment, which confirms the effectiveness of the model and the method.

2018 ◽  
Vol 183 ◽  
pp. 04005 ◽  
Author(s):  
Bar Nurel ◽  
Moshe Nahmany ◽  
Adin Stern ◽  
Nahum Frage ◽  
Oren Sadot

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.


2020 ◽  
Vol 1012 ◽  
pp. 89-93
Author(s):  
Anderson Oliveira da Silva ◽  
Ricardo Pondé Weber ◽  
Sergio Neves Monteiro

This work evaluates the mechanical and dynamic behavior of recycled polycarbonate (rPC) from industrial waste. This study aims to verify whether the recycled process adopted for polycarbonate promotes both mechanical and dynamic properties values under compressive stress, similar to those found for virgin polycarbonate. The mechanical recycling of the rPC was carried out using the thermoforming technique in a thermal press. Two tests were carried out to evaluate the dynamic response of rPC. The quasi-static compression test was performed on a universal machine. The dynamic in a split Hopkinson pressure bar was performed with three different strain rates. The results showed that the mechanical and primary recycling adopted in this work promoted values of yield stress in compression (77 MPa) and dynamic (up to 118 MPa), close to or superior to those reported so far in the literature.


2010 ◽  
Vol 129-131 ◽  
pp. 988-992
Author(s):  
Bo Wang ◽  
Tong Chen ◽  
Xue Feng Shu

In this paper, dynamic properties of EMC were studied at different temperatures and different strain rates. Firstly EMC was investigated by quasi-static tests. Secondly a series of dynamic compressive experiments of EMC were conducted using the Split Hopkinson Pressure Bar (SHPB) at sectional height of strain rates. Thirdly EMC constants in ZWT model were determined from experiments. Corresponding measurements were conducted at temperatures ranging from 20°C to 160°C. The results indicate that the yield strength and flow stress of EMC increase remarkably with the increase of strain rate and it is shows that the assembled curve is fit good accordance with actual the experimental curve. However, the yield strength of EMC is a little change with the increase of temperature which is ranging from 20°C to 160°C.


Author(s):  
S. Aghayan ◽  
S. Bieler ◽  
K. Weinberg

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.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5061
Author(s):  
Hafiz Fadillah ◽  
Sigit Puji Santosa ◽  
Leonardo Gunawan ◽  
Akbar Afdhal ◽  
Agus Purwanto

The dynamic behavior of the lithium-ion battery is evaluated by simulating the full battery system and each corresponding component, including the jellyroll and thin-foil electrodes. The thin-foil electrodes were evaluated using a novel design of split Hopkinson tensile bar (SHTB), while the jellyroll was evaluated using the split Hopkinson pressure bar (SHPB). A new stacking method was employed to strengthen the stress wave signal of the thin-foil electrodes in the SHTB simulation. The characteristic of the stress–strain curve should remain the same regardless of the amount of stacking. The jellyroll dynamic properties were characterized by using the SHPB method. The jellyroll was modeled with Fu-Chang foam and modified crushable foam and compared with experimental results at the loading speeds of 20 and 30 m/s. The dynamic behavior compared very well when it was modeled with Fu-Chang foam. These studies show that the dynamic characterization of Li-ion battery components can be evaluated using tensile loading of stacked layers of thin foil aluminum and copper with SHTB methodology as well as the compressive loading of jellyroll using SHPB methodology. Finally, the dynamic performance of the full system battery can be simulated by using the dynamic properties of each component, which were evaluated using the SHTB and SHPB methodologies.


2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Nan Wu ◽  
Zhende Zhu ◽  
Yaojun Zhou ◽  
Shihu Gao

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.


2018 ◽  
Vol 174 ◽  
pp. 02022 ◽  
Author(s):  
Anatoliy Bragov ◽  
Leonid Igumnov ◽  
Andrey Lomunov ◽  
Alexander Konstantinov ◽  
Dmitriy Lamzin ◽  
...  

The dynamic test techniques used to obtain the mechanical properties of brittle materials are described. The techniques are based on the fundamental Kolsky method using the Split-Hopkinson Pressure Bar. Dynamic tests are characterized by high intensity and short duration and the influence of inertia on their results should be ruled out which is especially important for brittle media. The prerequisites and assumptions presented methods are described to justify the validity of the obtained data. The methods allow to obtain dynamic deformation diagrams at compression, splitting, indirect tension, shear and triaxial stress state and also to determine the ultimate strength, strain and time properties of brittle materials. The techniques are approved in the tests of ceramic bricks, finegrain concrete and fiber-reinforced concrete.


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