scholarly journals Dynamic Response of Rock-like Materials Based on SHPB Pulse Waveform Characteristics

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 210
Author(s):  
Bi Sun ◽  
Rui Chen ◽  
Yang Ping ◽  
Zhende Zhu ◽  
Nan Wu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Strain Rate ◽  
Stress Wave ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Pulse Waveform ◽  
Inertia Effect ◽  
Critical Interval ◽  
Rate Gradient

Rock-like brittle materials under dynamic load will show more complex dynamic mechanical properties than those under static load. The relationship between pulse waveform characteristics and strain rate effect and inertia effect is rarely discussed in the split-Hopkinson pressure bar (SHPB) numerical simulation research. In response to this problem, this paper discusses the effects of different pulse types and pulse waveforms on the incident waveform and dynamic response characteristics of specimens based on particle flow code (PFC). The research identifies a critical interval of rock dynamic strength, where the dynamic strength of the specimen is independent of the strain rate but increases with the amplitude of the incident stress wave. When the critical interval is exceeded, the dynamic strength is determined by the strain rate and strain rate gradient. The strain rate of the specimen is only related to the slope of the incident stress wave and is independent of its amplitude. It is also determined that the inertia effect cannot be eliminated in the SHPB. The slope of the velocity pulse waveform determines the strain rate of the specimen, the slope of the force pulse waveform determines the strain rate gradient of the specimen, and the upper bottom time determines the strain rate of the specimen. It provides a reference for SHPB numerical simulation. A dynamic strength prediction model of rock-like materials is then proposed, which considers the effects of strain rate and strain rate gradient.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

scholarly journals Dynamic Characteristics of Deep Dolomite Under One-Dimensional Static and Dynamic Loads

2019 ◽  
Vol 101 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Jianguo Wang ◽  
Yang Liu ◽  
Kegang Li
Keyword(s):  
Strain Rate ◽  
Axial Compression ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Strong Positive Correlation ◽  
Hopkinson Pressure Bar ◽  
Irreversible Damage ◽  
One Dimensional ◽  
Rock Structure ◽  
The Impact

AbstractThe failure characteristics of rock subjected to impact disturbance under one-dimensional static axial compression are helpful for studying the problems of pillar instability and rock burst in deep, high geostress surrounding rock under blasting disturbances. Improved split Hopkinson pressure bar equipment was used for one-dimensional dynamic–static combined impact tests of deep-seated dolomite specimens under axial compression levels of 0, 12, 24, and 36 MPa. The experimental results demonstrate that the dolomite specimens exhibit strong brittleness. The dynamic strength always maintains a strong positive correlation with the strain rate when the axial compression is fixed; when the strain rate is close, the dynamic elasticity modulus and peak strength of the specimens first increase and then decrease with the increase in axial compression, and the peak value appears at 24 MPa. The impact resistance of specimens can be enhanced when the axial compression is 12 or 24 MPa, but when it increases to 36 MPa, the damage inside the specimen begins to cause damage to the dynamic rock strength. Prior to the rock macroscopic failure, the axial static load changes the rock structure state, and it can store strain energy or cause irreversible damage.

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.

Numerical Simulation of Stress Wave Propagation in Coal-Rock Combination Media

2012 ◽  
Vol 594-597 ◽  
pp. 542-551 ◽  
Author(s):  
Dong Jie Xue ◽  
Hong Wei Zhou ◽  
Jia Dun Liu ◽  
Hai Yang Yi
Keyword(s):  
Numerical Simulation ◽  
Strain Rate ◽  
Stress Wave ◽  
Incident Wave ◽  
Constant Strain Rate ◽  
Stress Wave Propagation ◽  
Propagation Mode ◽  
Reflected Wave ◽  
Strain And Strain Rate ◽  
Coal Rock

By establishing numerical simulation model of SPBH and comparing dynamic response of four kinds of coal-rock combination media subjected to three different stress waves, changes law of the reflected wave, incident wave, strain and strain rate were obtained. The results show that rock-rock combination has almost the same rules of reflected waves as rock-coal combination, coal-coal combination and coal-rock combination, while the coal-coal combination has the largest peak of reflected wave, followed by the coal-rock combination and the rock-coal combination, and the rock-rock combination ranks last. With increasing incident wave peak, the coal-rock combination weakens the peak more apparently. Strain softening occurs in coal samples under stress wave of peak value with the law that strain rate firstly increases, and then maintains a constant value, continues to increase and then decreases, increases reversely and then decreases. Constant strain rate of the phenomenon over time occurs. The results provide guidelines for both the study on propagation mode of stress wave in coal and rock combination media and the prevention of mining-induced dynamic disasters.

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.

Experimental Study on Dynamic Mechanical Behaviour of Concrete with High Temperature

2011 ◽  
Vol 194-196 ◽  
pp. 1109-1113 ◽  
Author(s):  
Bin Jia ◽  
Zheng Liang Li ◽  
Lu Cheng ◽  
Hua Chuan Yao
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Impact Velocity ◽  
Room Temperature ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Experimental System ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

An experimental system of high-temperature split Hopkinson pressure bar (SHPB) was developed by combination of the split Hopkinson pressure bar (SHPB) and microwave heating system, then tests of concrete whose temperature changed from room temperature to 650°С and impact velocity from 5m/s to 12m/s were completed. Based on the test results, the dynamic strength of concrete increases with increasing impact velocity whether with high temperature or room temperature, meanwhile the dynamic strength of concrete with high temperature has the strain rate effect, but the effect keeps decreasing with temperature increasing, even at temperature above 500°С , compressive strength will not have strain rate sensitive effect any longer when strain rate surpasses a certain value. In the meantime, the strain rate hardening effect is coupled with high temperature weakening effect, but the latter has greater influence.

Dynamic Mechanical Behaviour and Durability of Ultra-High Performance Cementitious Composite

2008 ◽  
Vol 400-402 ◽  
pp. 3-15 ◽  
Author(s):  
Wei Sun ◽  
Jian Zhong Lai
Keyword(s):  
Strain Rate ◽  
High Performance ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Cementitious Composite ◽  
Hopkinson Pressure Bar ◽  
Fiber Volume ◽  
Thaw Cycle

Ultra-high performance cementitious composite (UHPCC) with 200MPa compressive strength was prepared by substitution of ultra-fine industrial waste powder for 60% cement by weight. Compressive impact behaviour of UHPCC with different fiber volume fraction was researched by split Hopkinson pressure bar in four kinds of impact modes. Standard strength of UHPCC under impact was defined. The effects of strain rate, impact times, impact modes and fiber volume fraction on the properties of UHPCC under impact were researched. Results showed that impact resistance of UHPCC was improved with the increase of fiber volume fraction. With the increase of strain rate the dynamic strength of UHPCC was improved. With the increase of impact times the damage of material increased while the standard strength decreased. With the change of impact modes the damage of material on the first impact and the rate of the reduction of peak stress on the second and third impact increased. After a long time freezing-thaw cycle, corrosion and carbonation, results indicated that UHPCC had excellent durability.

Study on the Dynamic Behaviors of X70 Pipeline Steel by Numerical Simulation

2010 ◽  
Vol 97-101 ◽  
pp. 278-281 ◽  
Author(s):  
Xiu Li Zhang ◽  
Yi Ming Mi ◽  
Tao Ji ◽  
Hong Xia Xu ◽  
Yan Ting Xie ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Pipeline Steel ◽  
Element Model ◽  
Hopkinson Pressure Bar ◽  
X70 Pipeline Steel ◽  
Cook Model

Using the commercial code ANSTS/LS-DYNA, this study has established a Split Hopkinson Pressure Bar (SHPB) finite element model (FEM) of X70 pipeline steel. Moreover, the stress-strain behavior of X70 pipeline steel has been investigated by a simplified Johnson-Cook model. The stress and strain relationship of X70 pipeline steel under different compact speeds is obtained under the high strain rate of 103S-1. The results obtained by numerical simulation agree well with those by experiments, and the parameters of Johnson-Cook model describe accurately the mechanical behaviors of X70 pipe line steel under high strain rate. This conclusion will serve as an important reference for developing and applying materials.

Stress wave propagation effects in split Hopkinson pressure bar tests

1995 ◽  
Vol 449 (1936) ◽  
pp. 187-204 ◽  
Keyword(s):  
Wave Propagation ◽  
Strain Rate ◽  
Stress Wave ◽  
Split Hopkinson Pressure Bar ◽  
Rate Sensitivity ◽  
Stress Wave Propagation ◽  
Hopkinson Pressure Bar ◽  
Propagation Effects ◽  
Split Hopkinson ◽  
Pressure Bar

Studies of the properties of materials at high strain rates by the split Hopkinson pressure bar suggest that most materials show a sharp increase in strain rate sensitivity at high rates. In this paper, analytical and numerical evidence is presented which shows that his apparent increase in the strain rate sensitivity reported in the literature may result from stress wave propagation effects present in the test. A one-dimensional analytical solution has been developed for a rate independent bi-linear material tested in a split Hopkinson pressure bar apparatus. The solution, which is based on a stress wave reverberation model, shows that there is an apparent increase in the strain rate sensitivity of the material which can only be explained in terms of large propagating plastic wave fronts in the specimen. Numerical modelling of the same test geometry for the same input material model is in excellent agreement showing conclusively that stress wave propagation effects are inevitable at high impact velocities. The assumption of uniform stress and strain distribution within a split Hopkinson pressure bar specimen is therefore incorrect at high impact velocities. The formulation of the novel numerical code used in the present work, which is based on the finite volume technique, is also presented.

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