Dynamic Compression Behavior of Lotus-Type Porous Iron

2010 ◽  
Vol 658 ◽  
pp. 193-196
Author(s):  
Masakazu Tane ◽  
Tae Kawashima ◽  
Keitaro Horikawa ◽  
Hidetoshi Kobayashi ◽  
Hideo Nakajima

Dynamic and quasi-static compression tests were conducted on lotus-type porous iron with porosity of about 50% using the split Hopkinson pressure bar method and universal testing machine, respectively. In the dynamic compression parallel to the pore direction, a plateau stress region appears where deformation proceeds at nearly constant stress, while the plateau stress region does not appear in the quasi-static compression. The plateau stress region is probably caused by the buckling deformation of matrix iron which occurs only in the dynamic compression. In contrast, the compression perpendicular to the orientation direction of pores exhibits no plateau-stress regions in the both dynamic and quasi-static compression.

2013 ◽  
Vol 816-817 ◽  
pp. 84-89
Author(s):  
Yong Gang Kang ◽  
Yuan Yang ◽  
Jie Huang ◽  
Jing Hang Zhu

7075-T651 aluminum alloy are widely used in aeronautical applications such as wing panels, but there is no corresponding constitutive model for it now. In this paper, the flow behavior of 7050-T651 aluminum alloy was investigated by Split Hopkinson Pressure Bar (SHPB) and quasi-static compression experiment system. The strain hardening parameters were obtained by quasi-static compression experiment data, and the strain rate hardening parameters at various strain rates (1000-3000s-1) and room temperature, and the thermal softening parameter at various temperatures (20-300°C) where strain rate is 3000s-1 were obtained by SHPB experiment data. Then the constitutive equation of 7075-T651 aluminum alloy is obtained based on Johnson-Cook constitutive equation model.


2014 ◽  
Vol 487 ◽  
pp. 7-14 ◽  
Author(s):  
Xi Guang Deng ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Xiao Yun Song

This study derived the five parameters in Johnson-Cook equation of CP titanium Gr2. Quasi-static and dynamic compression tests were designed to measure mechanical properties at strain rates of 10-3s-1 and 6000s-1. In order to secure the validity of tested data, a novel fixture was proposed to reduce the displacement measurement error in MTS testing system and the signal processing procedure of compressive split Hopkinson pressure bar for the present study was demonstrated. With the tested data and calculated adiabatic heating temperature rise, parameters A, B, n, m, C have been derived based on mathematical deduction and solve. It was found that the constructed constitutive model fit the tested data well and was able to restore the yield strength value at high strain rate.


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.


2014 ◽  
Vol 566 ◽  
pp. 122-127
Author(s):  
Takayuki Kusaka ◽  
Takanori Kono ◽  
Yasutoshi Nomura ◽  
Hiroki Wakabayashi

A novel experimental method was proposed for characterizing the compressive properties of composite materials under impact loading. Split Hopkinson pressure bar system was employed to carry out the dynamic compression tests. The dynamic stress-strain relations could be precisely estimated by the proposed method, where the ramped input, generated by the plastic deformation of a zinc buffer, was effective to reduce the oscillation of the stress field in the specimen. The longitudinal strain of gage area could be estimated from the nominal deformation of gage area, and consequently the failure process could be grasped in detail from the stress-strain relation. The dynamic compressive strength of the material was slightly higher than the static compressive strength. In addition, the validity of the proposed method was confirmed by the computational and experimental results.


Author(s):  
Yihang Fan ◽  
Bing Wang ◽  
Zhaopeng Hao

In this study, the effects of strain rate and temperature on the flow stress of Inconel718 were analyzed by Split Hopkinson Pressure Bar (SHPB) experiment and quasi-static compression experiment. The classical JC constitutive model was established by combining the quasi-static compression experiment with the SHPB experiment. According to the effects of different grain sizes and [Formula: see text] phase on dislocation pile-up, the dislocation pile-up theory was introduced to modify the JC constitutive model. The modified constitutive model was compiled in FORTRAN language, and VUMAT user material subroutine was called and secondary development was carried out to establish the polycrystalline simulation model with different grain sizes. The uniaxial tensile and compression simulation process of polycrystal with different grain sizes was performed. Through comparing the simulation results with the experimental data. The correlation coefficient R, between the simulation and experimental values, is 0.97,981, and the average relative error is only 3.72%. The accuracy of the modified constitutive model was verified.


2012 ◽  
Vol 450-451 ◽  
pp. 523-526 ◽  
Author(s):  
Hai Feng Liu ◽  
Wei Wu Yang ◽  
Jian Guo Ning

The dynamic compression tests of reinforced concrete with different reinforcement ratios are carried out by split Hopkinson pressure bar (SHPB). Reinforced steel bar is placed along longitudinal and transverse direction. Experimental results show that reinforced concrete is non-linear and rate-dependent. With the enhancement of strain rate, the peak stress of reinforced concrete increases correspondingly


2010 ◽  
Vol 25 (6) ◽  
pp. 1179-1190 ◽  
Author(s):  
Masakazu Tane ◽  
Tae Kawashima ◽  
Hiroyuku Yamada ◽  
Keitaro Horikawa ◽  
Hidetoshi Kobayashi ◽  
...  

The strain rate dependence of anisotropic compression behavior in porous iron with cylindrical pores oriented in one direction was investigated. Through high strain rate (˜103 s−1) compression tests along the orientation direction of pores using the split Hopkinson pressure bar method, it was shown that the stress–strain curve exhibits a unique plateau-stress region where deformation proceeds with almost no stress increase. The appearance of the plateau-stress region is related to the buckling deformation of the iron matrix and provides superior energy absorption. However, for the middle (˜10−1 s−1) and low strain rates (˜10−4 s−1), compression along the same direction produces no such plateau region. In fact, in contrast to compression in the parallel direction, compression perpendicular to the orientation direction of pores produces no plateau-stress regions in any of the three strain rates.


2016 ◽  
Vol 693 ◽  
pp. 621-628 ◽  
Author(s):  
Xi Guo Xue ◽  
Li Jing Xie ◽  
Tao Wang

By conducting the quasi-static compression and split Hopkinson pressure bar testing,the flow strain - stress curves under strain rate range of 0.0001-1000/s and temperature range of normal-400°C of different volume fraction SiC particles reinforced metal matrix composite SiCp/6063Al were obtained. The commonly used Johnson-Cook constitutive model in metal materials was applied in this research. And on the basis of it, the influence of volume fraction to flow stress was utilized to establish the equivalent and homogeneous constitutive model.


Author(s):  
Jianyong Chen ◽  
Jun Liu ◽  
Yuansheng Cheng ◽  
Pan Zhang

Abstract Closed-cell stochastic foams are widely used in engineering field due to the excellent energy absorption capability. In this paper, the crushing response of three dimensional closed-cell foams is investigated under quasi-static and dynamic compression loading. Voronoi tessellation is employed to generate the mesoscale geometric models of closed-cell stochastic foams, and subsequently numerical analysis is carried out using LS-DYNA software. Results reveal that the plateau stress of Voronoi model under quasi-static compression linearly increases with the increase of relative density. In addition, the mechanical properties of Voronoi model under quasi-static and dynamic compression are related to a shear band collapse mode and a layer-wise collapse mode, respectively. The plateau stress and the densification strain under high-speed loading are higher than those under quasi-static and low-speed loading.


2021 ◽  
Vol 250 ◽  
pp. 03006
Author(s):  
Remigiusz Błoniarz ◽  
Janusz Majta ◽  
Carl P. Trujillo ◽  
Ellen K. Cerreta ◽  
Krzysztof Muszka

In the presented work two grades of steel i.e. microalloyed ferrite (M_F) and microalloyed austenite (M_A) where subjected to the grain refinement processes using MaxStrain system and thermomechanical rolling. The wide range of grain size, starting from 200 µm down to submicrometer level was produced in this way. The specimens of both steels were subjected to the dynamic compression tests using the Split Hopkinson Pressure Bar (SHPB) apparatus and applying the strain rates in the range between ε˙ = 3750s-1 and ε˙ = 6000s-1. In addition, different temperatures were used in the tests, i.e.200 °C and 400 °C. The first peak of stress which is observed during elastic-plastic transition during the dynamic compression tests can be treated as a characteristic feature of the tested material. The results obtained in the present investigations showed a significant dependence of the “first stress peak” in the dynamic compression curve on the degree of the microstructure refinement for the samples of M_F and almost complete absence of this dependence for M_A.


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