A Split-Hopkinson Tension Bar study on the dynamic strength of basalt-fibre composites

2019 ◽  
Vol 171 ◽  
pp. 310-319 ◽  
Author(s):  
G.C. Ganzenmüller ◽  
D. Plappert ◽  
A. Trippel ◽  
S. Hiermaier
Keyword(s):  
Dynamic Strength ◽  
Basalt Fibre ◽  
Fibre Composites ◽  
Split Hopkinson ◽  
Split Hopkinson Tension Bar

scholarly journals Stress Transfer Mechanism of Flange in Split Hopkinson Tension Bar

2020 ◽  
Vol 10 (21) ◽  
pp. 7601
Author(s):  
Hyunho Shin ◽  
Sanghoon Kim ◽  
Jong-Bong Kim
Keyword(s):  
Stress Transfer ◽  
Transfer Mechanism ◽  
Explicit Finite Element ◽  
Impact Theory ◽  
Quantitative Basis ◽  
Split Hopkinson ◽  
One Step ◽  
The One ◽  
The Impact ◽  
Split Hopkinson Tension Bar

To reveal the stress transfer mechanism of the flange in a split Hopkinson tension bar, explicit finite element analyses of the impact of the hollow striker on the flange were performed across a range of flange lengths. The tensile stress profiles monitored at the strain gauge position of the incident bar are interpreted on a qualitative basis using three types of stress waves: bar (B) waves, flange (F) waves, and a series of reverberation (Rn) waves. When the flange length (Lf) is long (i.e., Lf > Ls, where Ls is the striker length), the B wave and first reverberation wave (R1) are fully separated in the time axis. When the flange length is intermediate (~Db < Lf < Ls, where Db is the bar diameter), the B and F waves are partially superposed; the F wave is delayed, then followed by a series of Rn waves after the superposition period. When the flange length is short (Lf < ~Db), the B and F waves are practically fully superposed and form a pseudo-one-step pulse, indicating the necessity of a short flange length to achieve a neat tensile pulse. The magnitudes and periods of the monitored pulses are consistent with the analysis results using the one-dimensional impact theory, including a recently formulated equation for impact-induced stress when the areas of the striker and bar are different, equations for the reflection/transmission ratios of a stress wave, and an equation for pulse duration time. This observation verifies the flange length-dependent stress transfer mechanism on a quantitative basis.

Micromechanics Analysis of the Tensile Behavior of Twaron Fiber Tows at Various Strain Rates

2011 ◽  
Vol 181-182 ◽  
pp. 749-753
Author(s):  
Lv Tao Zhu ◽  
Bao Zhong Sun
Keyword(s):  
Mechanical Properties ◽  
Fracture Surface ◽  
Strain Rate ◽  
Failure Strain ◽  
Tensile Behavior ◽  
Failure Stress ◽  
Strain Rates ◽  
Split Hopkinson ◽  
Electronic Microscope ◽  
Split Hopkinson Tension Bar

In this study, tensile experiments of Twaron fiber tows under different strain rates (quasi-static:0.001s-1, dynamic: 800s-1~2400s-1) were carried out with MTS 810.23 materials tester and split Hopkinson tension bar (SHTB) respectively. The results showed that the mechanical properties of the Twaron fiber tows were sensitive to strain rate: the stiffness and failure stress of the fiber tows increased distinctly as the strain rate increased, while the failure strain decreased. From scanning electronic microscope (SEM) photographs of the fracture surface, it is indicated that the Twaron fiber tows failed in a more tough mode and the axial split will become more severe as the strain rate increases.

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.

Loading and Unloading Split Hopkinson Tension Bar Technique for Studying Dynamic Microstructure Evolution of Materials

2010 ◽  
Vol 160-162 ◽  
pp. 891-894 ◽  
Author(s):  
Wen Huang ◽  
Zhong Wei Huang ◽  
Xiao Qing Zhou
Keyword(s):  
Microstructure Evolution ◽  
Pure Titanium ◽  
Dynamic Mechanical Properties ◽  
Post Test ◽  
Split Hopkinson ◽  
Adiabatic Curve ◽  
Loading And Unloading ◽  
Different Strains ◽  
Strength And Ductility ◽  
Split Hopkinson Tension Bar

In order to investigate the microstructure evolution of materials, loading and unloading experiments with specimens deformed at different strains are required. In this paper, momentum traps were introduced for rendering the conventional Split Hopkinson Tension Bar suitable for loading-unloading experiment. The new technique allows a specimen to be loaded to a preset strain for post-test characterization. This technique was applied to study the dynamic mechanical properties of pure titanium. The results show that: 1) the twinning density of titanium increases rapidly as the strain increases. 2) The strength and ductility of titanium exhibited on the adiabatic curve are much smaller then those exhibited on the isothermal curve, which may be caused by the adiabatic heat generated during the transient deformation process.

Interfacial bond behaviour between hybrid carbon/basalt fibre composites and concrete under dynamic loading

2020 ◽  
Vol 99 ◽  
pp. 102569 ◽  
Author(s):  
Cheng Yuan ◽  
Wensu Chen ◽  
Thong M. Pham ◽  
Hong Hao ◽  
Jian Cui ◽  
...  
Keyword(s):  
Dynamic Loading ◽  
Interfacial Bond ◽  
Basalt Fibre ◽  
Bond Behaviour ◽  
Fibre Composites ◽  
Hybrid Carbon

scholarly journals Effect of Acid and Alkaline Environment on Dynamic Strength and Porosity Characteristics of Bursting Liability Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lei Li ◽  
Jiangbo Fan ◽  
Ningning Liu ◽  
Shuang Gong ◽  
Daming Yang
Keyword(s):  
Tensile Strength ◽  
Dynamic Strength ◽  
Xrd Analysis ◽  
Acidic Environment ◽  
Shear Cracks ◽  
X Ray Diffraction ◽  
Alkaline Environment ◽  
Surface Micromorphology ◽  
Alkaline Environments ◽  
Split Hopkinson

In order to investigate the influence of acid and alkaline environment on dynamic strength and porosity characteristics of bursting liability coal, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used to compare the microstructures of coal with different bursting liabilities. A split Hopkinson bar (SHPB) was used to test the dynamic compressive strength and tensile strength of coal samples with different bursting liabilities. The results show that the surface micromorphology and structure characteristics of coal samples with different bursting liabilities are representatives, which can be used as an auxiliary basis to determine the bursting liability of coal seam. The microstructure of coal with strong bursting liability is characterized by mylonitic, fragmentary, and brecciated structure, and the microstructure is diverse and complex. However, the microstructure of no bursting liability coal is single and uniform. Coal with strong bursting liability shows tensile, compressive, and shear cracks produced by tectonic action, and the distribution of cracks is complicated. The development of fissures is greatly affected by the degree of coal metamorphism, organic components, minerals, and other factors. Under acidic and alkaline environments, the decrease amplitude of tensile strength of coal is obviously larger than that in neutral solution, which indicates that under the action of acid-based solution soaking, the easily soluble minerals in coal react with hydrogen ions and hydroxyl ions in solution obviously. Porosity increment in acidic environment is much larger than that in alkaline and neutral environments. The strong bursting liability coal is more sensitive to acidic environment, while the no bursting liability coal is more sensitive to alkaline environment.

scholarly journals Combined shear/tension testing of fibre composites at high strain rates using an image-based inertial impact test

2018 ◽  
Vol 183 ◽  
pp. 02041 ◽  
Author(s):  
Lloyd Fletcher ◽  
Jared Van-Blitterswyk ◽  
Fabrice Pierron
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Stress Wave ◽  
Impact Test ◽  
High Strain ◽  
Hopkinson Bar ◽  
Test Method ◽  
Strain Rates ◽  
Fibre Composites ◽  
Split Hopkinson

Testing fibre composites off-axis has been used extensively to explore shear/tension coupling effects. However, off-axis testing at strain rates above 500 s-1 is challenging with a split Hopkinson bar apparatus. This is primarily due to the effects of inertia, which violate the assumption of stress equilibrium necessary to infer stress and strain from point measurements taken on the bars. Therefore, there is a need to develop new high strain rate test methods that do not rely on the assumptions of split Hopkinson bar analysis. Recently, a new image-based inertial impact test has been used to successfully identify the transverse modulus and tensile strength of a unidirectional composite at strain rates on the order of 2000 -1. The image-based inertial impact test method uses a reflected compressive stress wave to generate tensile stress and failure in an impacted specimen. Thus, the purpose of this study is to modify the image-based inertial impact test method to investigate the high strain rate properties of fibre composites using an off-axis configuration. For an off-axis specimen, a combined shear/tension or shear/compression stress state will be obtained. Throughout the propagation of the stress wave, full-field displacement measurements are taken. Strain and acceleration fields are then derived from the displacement fields. The kinematic fields are then processed with the virtual fields method (VFM) to reconstruct stress averages and identify the in-plane stiffness components G12 and E22.

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