scholarly journals Numerical Modeling of a Split Hopkinson Pressure Bar Test

2021 ◽  
Vol 6 (3) ◽  
pp. 53-57
Author(s):  
Ahmad R. Aljohani ◽  
Ramzi Othman ◽  
Khalid H. Almitani
Keyword(s):  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Dimensional Model ◽  
Hopkinson Pressure Bar ◽  
One Dimensional ◽  
Strain And Strain Rate ◽  
Split Hopkinson ◽  
Bar Test ◽  
Pressure Bar

In this work, a one-dimensional simplified model was developed to predict stress, strain, and strain-rate in high strain rates Hopkinson pressure bar experiments, namely, between 500-5000/s. To this goal, a one-dimensional model for Hokinson bar tests was developed based on analyses of wave propagation in bars and assuming the specimen is under equilibrium during the test. The numerical tool implemented using Matlab and validated regarding experimental data. This new model will be very helpful in designing the specimens for split Hopkinson bar tests and also in the interpretation of the experimental raw data.

Using Split Hopkinson Pressure Bars to Perform Large Strain Compression Tests on Neoprene at Intermediate and High Strain Rates

2013 ◽  
Vol 631-632 ◽  
pp. 458-462 ◽  
Author(s):  
Peng Duo Zhao ◽  
Yu Wang ◽  
Jian Ye Du ◽  
Lei Zhang ◽  
Zhi Peng Du ◽  
...  
Keyword(s):  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Large Strain ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
High Strain Rates ◽  
Split Hopkinson ◽  
Pressure Bar

The strain rate sensitivity of neoprene is characterized using a modified split Hopkinson pressure bar (SHPB) system at intermediate (50 s-1, 100 s-1) and high (500 s-1, 1000 s-1) strain rates. We used two quartz piezoelectric force transducers that were sandwiched between the specimen and experimental bars respectively to directly measure the weak wave signals. A laser gap gage was employed to monitor the deformation of the sample directly. Three kinds of neoprene rubbers (Shore hardness: SHA60, SHA65, and SHA70) were tested using the modified split Hopkinson pressure bar. Experimental results show that the modified apparatus is effective and reliable for determining the compressive stress-strain responses of neoprene at intermediate and high strain rates.

scholarly journals Large Deformation Behavior of High Strength Steel Under Extreme Loading Conditions: High Temperature and High Strain Rate Experiments and Modeling

2018 ◽  
Vol 183 ◽  
pp. 01053
Author(s):  
Xueyang Li ◽  
Christian C. Roth ◽  
Dirk Mohr
Keyword(s):  
Strain Hardening ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
High Strength ◽  
Fracture Initiation ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Temperature Dependent ◽  
Split Hopkinson ◽  
Pressure Bar

Plasticity and fracture experiments are carried out on flat smooth and notched tensile specimens extracted from DP800 steel sheets. A split Hopkinson pressure bar testing system equipped with a load inversion device is utilized to reach high strain rates. Temperature dependent experiments ranging from 20°C to 300°C are performed at quasi-static strain rates. The material exposes a monotonic strain hardening behaviour with a non-monotonic temperature dependency. The rate-independent material behaviour at room-temperature is described with a non-associated Hill’48 plasticity model and an Swift-Voce strain hardening. A machine learning based model is used multiplicatively to capture the rate and temperature responses. A good agreement between measured and simulated force-displacement curves as well as local surface is obtained. The loading paths to fracture are then extracted to facilitate further development of a temperature dependent fracture initiation model.

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.

Deformation Behavior of Ti-6Al-4V-0.1B Alloy Loaded under High Strain Rates

2016 ◽  
Vol 849 ◽  
pp. 266-270 ◽  
Author(s):  
Yang Yu ◽  
Qi Gao ◽  
Xun Jun Mi ◽  
Song Xiao Hui ◽  
Wen Jun Ye
Keyword(s):  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
High Strain Rates ◽  
The Matrix ◽  
Split Hopkinson ◽  
Pressure Bar

Deformation and fracture behaviors of Ti-6Al-4V-0.1B alloy with Widmanstätten, equiaxed and bimodal microstructures were investigated by Split Hopkinson Pressure Bar (SHPB) under high strain rates of 2100-3200 s-1. The results showed that the equiaxed and bimodal structures had a higher bearing capacity at high strain rates than that of the Widmanstätten structure. With the same microstructure, the increase of strain rate gave rise to an improved uniform plastic deformation. According to an observation on the deformed microstructure, it was found that adiabatic shear behavior was the main reason for failure and fracture of the alloy. The formation and propagation of adiabatic shear bands (ASBs) was the precursor for the failure and fracture of the material. Cavities at the interface between TiB phase and the matrix readily formed due to the uncoordinated deformation, which are not the dominate reason for the failure and fracture.

scholarly journals Dynamic tensile strength enhancement of concrete in split Hopkinson pressure bar test

2018 ◽  
Vol 10 (6) ◽  
pp. 168781401878230 ◽  
Author(s):  
Jingyi Chen ◽  
Da Xiang ◽  
Zhihua Wang ◽  
Guiying Wu ◽  
Genwei Wang
Keyword(s):  
Tensile Strength ◽  
Split Hopkinson Pressure Bar ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
Dynamic Tensile Strength ◽  
Concrete Material ◽  
Split Hopkinson ◽  
Bar Test ◽  
Concrete Materials ◽  
Pressure Bar

Split Hopkinson pressure bar technique has been widely used to measure the dynamic tensile strength of concrete materials. Most experimental results show that the tensile strength of concrete material increases with strain rates. However, the dynamic tensile strength derived from the split Hopkinson pressure bar test is affected by lateral inertia confinement, which may lead to the overestimation of dynamic mechanical properties of concrete materials. The true dynamic characteristics of concrete materials are not actually shown by experimental data. It is impossible to completely eliminate the influence of lateral inertia confinement in split Hopkinson pressure bar tests. In this study, a rate-insensitive material model is used in commercial finite element software to study how the lateral inertia confinement affects the dynamic tensile strength of concrete material at strain rates between 30/s and 150/s. Comparison of finite element results and split Hopkinson pressure bar test results shows that the dynamic tensile strength enhancement of concrete materials is strongly influenced by the inertial effect. The dynamic increase factor of concrete materials which remove the influence of lateral inertia confinement in split Hopkinson pressure bar tests can reflect the true dynamic characteristics of concrete materials. It is also found that the influence of lateral inertia confinement is related to the size of the specimen.

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