scholarly journals Effect of the Confining Pressure on the Dynamic Compression Properties of Transversely Isotropic Rocks

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xuefeng Ou ◽  
Xuemin Zhang ◽  
Han Feng ◽  
Cong Zhang ◽  
Junsheng Yang
Keyword(s):  
Young’S Modulus ◽  
Split Hopkinson Pressure Bar ◽  
Young's Modulus ◽  
Dynamic Compression ◽  
Dynamic Strength ◽  
Transversely Isotropic ◽  
Confining Pressure ◽  
Bedding Plane ◽  
Hopkinson Pressure Bar ◽  
Compression Properties

The dynamic compression properties of transversely isotropic rocks and their dependence on the confining pressure and bedding directivity are important in deep underground engineering activities. In this study, a slate is characterized using a split Hopkinson pressure bar (SHPB) test. Five groups of samples with preferred bedding directions (dip angles of 0°, 30°, 45°, 60°, and 90°) are subjected to coupled axial impact loading (low, medium, and high) under confining pressure (0, 5, and 10 MPa). The failure mode, dynamic strength, and Young’s modulus are investigated. The test results show that the tensile splitting effect is significant when there is no confining pressure. However, under a confining pressure (5 and 10 MPa) condition, the cracks that develop along the loading direction can be significantly constrained and the samples are forced to fail along the bedding plane. With increasing confining pressure, the critical dynamic strength significantly increases, and Young’s modulus increases when θ≥45° while it decreases when θ≤30°.

Dynamic Compression Properties of Ti-6Al-4V Titanium Alloy Extruded Sections

2017 ◽  
Vol 898 ◽  
pp. 199-203 ◽  
Author(s):  
Rui Liu ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Yang Yu ◽  
Xiao Yun Song
Keyword(s):  
Plastic Deformation ◽  
Titanium Alloy ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Dynamic Strength ◽  
Hopkinson Pressure Bar ◽  
Compression Properties ◽  
Coarse Grains ◽  
Pressure Bar ◽  
Conventional Annealing

This paper aimed to study the dynamic compression properties of Ti-6Al-4V titanium alloy sections. The Ti-6Al-4V sections were extruded above the β-transus temperature with extruding ratio of 85, and then heat treated by conventional annealing at 750°C, or annealing at 1200°C by two routes. Dynamic compression properties were investigated by Split Hopkinson Pressure Bar system at strain rate of 3000±200 s-1. The results show that the dynamic compression properties of as-extruded specimens are comparable to the specimens after conventional annealing at 750°C. Compared to Widmannstatten microstructure with original beta grains in size of 200 μm ~ 300 μm obtained by conventional annealing, the microstructure obtained by annealing at 1200°C with coarse grains consisted of fine α-lamellae exhibits comparable dynamic strength but the capability of plastic deformation reduced about 20%. For the microstructure obtained by annealing at 1200°C with coarse grains consisted of coarse α-lamellae, the dynamic strength slightly decreased, while the capability of plastic deformation reduced about 60%.

Quasi-Static and Dynamic Properties of Ti-3.5Al-2.5V-1.5Fe-0.25O Titanium Alloy Plates

2016 ◽  
Vol 879 ◽  
pp. 1159-1163 ◽  
Author(s):  
Rui Liu ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Rong Chen ◽  
Yang Yu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Dynamic Compression ◽  
Dynamic Strength ◽  
Nominal Composition ◽  
Hopkinson Pressure Bar ◽  
Alloy Plate ◽  
Compression Properties

This paper aimed to study the quasi-static and dynamic properties of a titanium alloy plate with nominal composition Ti-3.5Al-2.5V-1.5Fe-0.25O (ATI 425TM titanium alloy with lower limit of Al element) in thickness of 8 mm. The quasi-static tensile properties were investigated by MTSTM testing system at strain rate of 10-3 s-1, while dynamic compression properties by Split Hopkinson Pressure Bar system at strain rate of 3000±200 s-1. The results show that the quasi-static prperties of the Ti-3.5Al-2.5V-1.5Fe-0.25O plate are comparable to the commercial Ti-6Al-4V plate in 8mm-thick. The Ti-3.5Al-2.5V-1.5Fe-0.25O plate exhibats good dynamic strength. The average dynamic flow stress is 100MPa higher than that of Ti-6Al-4V plate. However, the maximum strain during homogeneous plastic deformation of Ti-3.5Al-2.5V-1.5Fe-0.25O plate is only 50~60% of that of Ti-6Al-4V plate.

Microstructures and Dynamic Compression Properties of a High Reinforcement Content TiB2/Al Composite

2007 ◽  
Vol 546-549 ◽  
pp. 639-642
Author(s):  
De Zhi Zhu ◽  
Gao Hui Wu ◽  
Long Tao Jiang ◽  
Guo Qin Chen
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Shear Fracture ◽  
Dynamic Compression ◽  
Average Particle Size ◽  
Average Particle ◽  
Hopkinson Pressure Bar ◽  
Compression Properties ◽  
Reinforcement Content ◽  
Al Composite

A high reinforcement content TiB2/2024Al composite with an average particle size of 8μm was fabricated by squeeze casting technology. The dynamic compression behaviors of the composite under varied strain rates were measured using split Hopkinson pressure bar, and its microstructure and fracture characteristic were examined. Resluts revealed that the composite was dense and homogenerous, and the TiB2-Al interface was clean without interfacial reactants. At high strain rate, the TiB2/Al composite showed insensitive to the strain rate, and both the flow stress and the elastic modulus improved little with an increase of the strain rate. The composite failed macroscopically in shear fracture and in split, which were caused by cracking of large reinforcement particles and interface failures under dynamic load.

Dynamic Compression Performance of Reaction Sintering SiC/B4C Composite

2020 ◽  
Vol 999 ◽  
pp. 83-90
Author(s):  
Xiao Ju Gao ◽  
Hasigaowa ◽  
Meng Yong Sun ◽  
Cheng Dong Liao ◽  
Wei Ping Huang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Dynamic Strength ◽  
Reaction Sintering ◽  
Hopkinson Pressure Bar ◽  
Compression Performance ◽  
Loading Mode ◽  
Split Hopkinson ◽  
Pressure Bar

SiC/B4C composite was obtained using the reaction sintering method with Si infiltration, which exhibited excellent mechanical properties. The dynamic compressive response was investigated using a Split Hopkinson pressure bar at high strain rates ranging from 0.4×103 to 1.2×103 s-1. The results show that the dynamic strength of the SiC/B4C composite obtains a peak value at a strain rate of 1000/s, while its strain increased continuously with increasing strain rate. The dynamic loading mode of SiC/B4C composite exhibited three deformation regions, including an inelastic deformation region, rapid loading region and failure region. The dynamic failure mode of SiC/B4C composite depended upon the strain rate.

Dynamic Compression Behavior of Ti-6Al-4V Plates Prepared by a Single Electron Beam Cold Hearth Melted Ingot

2014 ◽  
Vol 1015 ◽  
pp. 328-331 ◽  
Author(s):  
Rui Liu ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Yang Yu ◽  
Yan Yan Fu ◽  
...  
Keyword(s):  
Electron Beam ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Dynamic Compression ◽  
Alpha Phase ◽  
Single Electron ◽  
Hopkinson Pressure Bar ◽  
Weight Percentage ◽  
Compression Properties ◽  
Pressure Bar

Ti-6Al-4V plates in thickness of 8 mm were directly hot rolled and then heat treated in various routes by a single electron beam cold hearth melted (EBCHM) ingot, in which the weight percentage of recycled titanium scraps was at least about 50 wt%. The dynamic stress-strain behaviors of the plates with typical microstructures were investigated by Split Hopkinson Pressure Bar system at the strain rates of 2000 s-1~ 3000 s-1. The results show that the dynamic compression properties of EBCHM-ingot Ti-6Al-4V plates are relative to that of commercial VAR-ingot plates. The dynamic properties in normal direction of the plates are not sensitive to variations in the fraction of primary alpha phase.

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.

Dynamic Compression Properties of Low-Cost Ti-6Al-4V Plates

2016 ◽  
Vol 849 ◽  
pp. 276-280
Author(s):  
Rui Liu ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Yang Yu ◽  
Yan Yan Fu ◽  
...  
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Low Cost ◽  
Hopkinson Pressure Bar ◽  
Homogeneous Microstructure ◽  
Strain Behavior ◽  
Compression Properties ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Hot Rolled

Ti-6Al-4V ingot with rectangle cross-section was directly manufactured by a single electron beam cold hearth melting (EBCHM) process, in which 65 wt.% recycled titanium scraps was used. The dynamic stress-strain behavior of the low-cost Ti-6Al-4V plates after heat treatment was investigated by Split Hopkinson Pressure Bar system at the strain rates of 2000 s-1~ 3000 s-1. The results showed that the plates with homogeneous microstructure could be obtained after two-heats hot rolled. The dynamic compression properties of low-cost Ti-6Al-4V plates in three different thicknesses were in the same level, which is comparable with that of commercial Ti-6Al-4V plates.

Construction of Johnson-Cook Model for Gr2 Titanium through Adiabatic Heating Calculation

2014 ◽  
Vol 487 ◽  
pp. 7-14 ◽  
Author(s):  
Xi Guang Deng ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Xiao Yun Song
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Heating Temperature ◽  
Dynamic Compression ◽  
Adiabatic Heating ◽  
Model Fit ◽  
Testing System ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

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.

A comparative study on dynamic mechanical performance of concrete and rock

2015 ◽  
Author(s):  
Xia Zhengbing ◽  
Zhang Kefeng ◽  
Deng Yanfeng ◽  
Ge Fuwen
Keyword(s):  
Mechanical Performance ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Peak Strain ◽  
Hopkinson Pressure Bar ◽  
Dynamic Mechanical ◽  
Strain And Strain Rate ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Relationship Of

Recently, engineering blasting is widely applied in projects such as rock mineral mining, construction of underground cavities and field-leveling excavation. Dynamic mechanical performance of rocks has been gradually attached importance both in China and abroad. Concrete and rock are two kinds of the most frequently used engineering materials and also frequently used as experimental objects currently. To compare dynamic mechanical performance of these two materials, this study performed dynamic compression test with five different strain rates on concrete and rock using Split Hopkinson Pressure Bar (SHPB) to obtain basic dynamic mechanical parameters of them and then summarized the relationship of dynamic compressive strength, peak strain and strain rate of two materials. Moreover, specific energy absorption is introduced to confirm dynamic damage mechanisms of concrete and rock materials. This work can not only help to improve working efficiency to the largest extent but also ensure the smooth development of engineering, providing rich theoretical guidance for development of related engineering in the future.

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