Experimental Study on Impact Compression and Spliting of Granite

2011 ◽  
Vol 117-119 ◽  
pp. 62-66
Author(s):  
Wan Peng Wang ◽  
Yong Le Hu ◽  
Xing Tao Ren ◽  
Yi Bo Xiong ◽  
Liang Ying
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Failure Strain ◽  
Dynamic Compression ◽  
Tensile Failure ◽  
Experimental Result ◽  
Strain Rates ◽  
Dynamic Tensile Strength ◽  
Impact Compression

In order to systematically study on dynamic mechanics character of granite, impact compression experiments and impact flattened Brazilian disc specimens of granite have been investigated with modified split Hopkinson pressure bar (SHPB) experimental facility, curve about stress versus strain and other parameter at strain rates of 23.9/s～108.4/s were obtained from impact compression. The dynamic tensile strength and critical tensile failure strain at strain rates of 2.3/s～25.6/s were obtained from impact flattened Brazilian. The experimental result show that dynamic compression strength , elastic modulus and failure strain，dynamic tensile strength significantly increase comparing to quasi-static experiment, and the above mechanics parameter include dynamic strength etc will increase with strain rate increasing, granite have the character of impact harding and ductility enhancement. The failure degree of failure will increase with increasing strain rate under impact compression; the failure configurations of the specimens present an center splitting mode under impact flattened Brazilian experiments. Whether impact compression or impact splitting under strain rate including this paper ’s experiments, the relationship between the DIFC or DIFT and the logarithm of strain rate is linear.

Impact Experimental Study for Dynamic Character of Reactive Powder Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 187-191
Author(s):  
Wan Peng Wang ◽  
Yong Le Hu ◽  
Xin Tao Ren ◽  
Yi Bo Xiong ◽  
Kang Zhao ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Failure Strain ◽  
Test System ◽  
Experimental Result ◽  
Reactive Powder Concrete ◽  
Strain Rates ◽  
Dynamic Tensile Strength ◽  
Impact Compression ◽  
Reactive Powder

In order to systematically study dynamic mechanics character of reactive powder concrete (RPC), impact compression experiments and impact flattened Brazilian disc specimens of RPC have been investigated with modified split Hopkinson pressure bar (SHPB) experimental facility using brass pulse shaper, curves about stress versus strain and other parameters at strain rates of 20.3/s~137.0/s were obtained from impact compression. The dynamic tensile strength and tensile failure strain at strain rates of 3.4/s~26.2/s were obtained from impact flattened Brazilian. For comparison, the quasi-static compress and split tension of RPC were obtained with an MTS 810 materials test system and CSS-88500 electron universal material testing machine.The experimental result show that dynamic compression strength , elastic modulus and failure strain,dynamic tensile strength and failure strain significantly increase comparing to quasi-static experiment, RPC have the character of impact harding and ductility enhancement. RPC exhibit excellent failure patterns at high strain rate. Whether impact compression or impact splitting under strain rate including this paper ’s experiments, the relationship between the DIFC or DIFT and the logarithm of strain rateis linear.

scholarly journals Numerical Study of Concrete Dynamic Splitting Based on 3D Realistic Aggregate Mesoscopic Model

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1948
Author(s):  
Qi Yu ◽  
Zhan-yang Chen ◽  
Jun Yang ◽  
Kai Rong
Keyword(s):  
Tensile Strength ◽  
Constitutive Model ◽  
Strain Rate ◽  
Transition Zone ◽  
Split Hopkinson Pressure Bar ◽  
Numerical Study ◽  
Dynamic Compression ◽  
Interfacial Transition Zone ◽  
Dynamic Tensile Strength ◽  
Mesoscopic Structure

In mesoscopic scale, concrete is regarded as a heterogeneous three-phase material composed of mortar, aggregate and interfacial transition zone (ITZ). The effect of mesoscopic structure on the mechanical behaviors of concrete should be paid more attention. The fractal characteristics of aggregate were calculated, then the geometric models of aggregate were reconstructed by using fractal Brownian motion. Based on the random distribution of aggregates, the concrete mesoscopic structure model was established. And the numerical model was generated by using grid mapping technology. The dynamic compression experiments of concrete under Split Hopkinson Pressure Bar (SHPB) loading verify the reliability and validity of the mesoscopic structural model and the parameters of the constitutive model. Based on these, a numerical study of concrete under dynamic splitting is carried out. By changing the parameters of the constitutive model, the effects of tensile strengths of aggregate, mortar and ITZ on the dynamic tensile strength of concrete are discussed. The results show that the dynamic failure of specimen usually occurs at the interfacial transition zone, then extends to the mortar, and the aggregates rarely fail. However, the increase of strain rate intensifies this process. When the strain rate increases from 72.93 s−1 to 186.51 s−1, a large number of aggregate elements are deleted due to reaching the failure threshold. The variation of tensile strengths of each phase component have the same effect on the dynamic tensile strength and energy of concrete. The dynamic tensile strength and energy of concrete are most affected by the tensile strength of mortar, following by the ITZ, but the tensile strength of aggregate has almost no effect.

Strain-Rate Dependence of Compressive Yield Strength of Titanium Grade 4 with Coarse-Grained and Ultrafine-Grained Structures: Experimental Results and Theoretical Calculation

2018 ◽  
Vol 1145 ◽  
pp. 100-105
Author(s):  
Ivan V. Smirnov ◽  
Alexander Y. Konstantinov
Keyword(s):  
Yield Strength ◽  
Strain Rate ◽  
Yield Stress ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Pure Titanium ◽  
Coarse Grained ◽  
Strain Rates ◽  
Ultrafine Grained ◽  
Titanium Grade

The nanocrystalline (NC) and ultrafine-grained (UFG) structures of metallic materials can lead to their extraordinary high strength. However, most of the papers on this topic consider deformation parameters of NC and UFG materials only for the case of quasi-static tensile tests. Characteristics of dynamic strength and fracture of such materials remain unexplored. This paper presents a study of the mechanical behavior of pure titanium Grade 4 with a coarse-grained (CG) and UFG structure under uniaxial compression with different strain rates. The UFG structure was provided using the method of equal-channel angular pressing. The dynamic compression was carried out on a setup with the Split-Hopkinson pressure bar. It is found that in the observed range of strain rates 10–3-3×103 s–1, the yield stress of the CG titanium increases by 20%, and does not exceed the yield stress of the UFG titanium. However, the yield stress of the UFG titanium remains close to a quasi-static value. It is shown that these strain-rate dependencies of the yield strength can be predicted by the incubation time approach. The calculated curves show that at strain rates above 104 s–1 the yield stress of the CG titanium becomes higher than the yield strength of the UFG titanium.

scholarly journals Experimental and Numerical Study on Tensile Strength of Concrete under Different Strain Rates

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Fanlu Min ◽  
Zhanhu Yao ◽  
Teng Jiang
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Numerical Study ◽  
Material Behavior ◽  
Constitutive Law ◽  
Test Machine ◽  
Strain Rates ◽  
Dynamic Tensile Strength ◽  
Dynamic Increase Factor ◽  
Versus Strain

The dynamic characterization of concrete is fundamental to understand the material behavior in case of heavy earthquakes and dynamic events. The implementation of material constitutive law is of capital importance for the numerical simulation of the dynamic processes as those caused by earthquakes. Splitting tensile concrete specimens were tested at strain rates of 10−7 s−1to 10−4 s−1in an MTS material test machine. Results of tensile strength versus strain rate are presented and compared with compressive strength and existing models at similar strain rates. Dynamic increase factor versus strain rate curves for tensile strength were also evaluated and discussed. The same tensile data are compared with strength data using a thermodynamic model. Results of the tests show a significant strain rate sensitive behavior, exhibiting dynamic tensile strength increasing with strain rate. In the quasistatic strain rate regime, the existing models often underestimate the experimental results. The thermodynamic theory for the splitting tensile strength of concrete satisfactorily describes the experimental findings of strength as effect of strain rates.

High Strain Rate Behavior of Carbon Nanotubes Reinforced Aluminum Foams

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Abdelhakim Aldoshan ◽  
D. P. Mondal ◽  
Sanjeev Khanna
Keyword(s):  
Carbon Nanotubes ◽  
Strain Rate ◽  
Aluminum Foam ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Strain Rates ◽  
Aluminum Foams ◽  
Static Compression ◽  
Closed Cell

The mechanical behavior of closed-cell aluminum foam composites under different compressive loadings has been investigated. Closed-cell aluminum foam composites made using the liquid metallurgy route were reinforced with multiwalled carbon nanotubes (CNTs) with different concentrations, namely, 1%, 2%, and 3% by weight. The reinforced foams were experimentally tested under dynamic compression using the split Hopkinson pressure bar (SHPB) system over a range of strain rates (up to 2200 s−1). For comparison, aluminum foams were also tested under quasi-static compression. It was observed that closed-cell aluminum foam composites are strain rate sensitive. The mechanical properties of CNT reinforced Al-foams, namely, yield stress, plateau stress, and energy absorption capacity are significantly higher than that of monolithic Al-foam under both low and high strain rates.

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.

Tensile Strength of Concrete at Different Strain Rates

1985 ◽  
Vol 64 ◽  
Author(s):  
Parviz Soroushian ◽  
Ki-Bong Choi ◽  
Gung Fu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Moisture Content ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Direct Tension ◽  
Dynamic Tensile Strength ◽  
Strength Tests ◽  
Compressive Strength Of Concrete

ABSTRACTResults of dynamic tensile strength tests of concrete, produced by the authors and other investigators, were used to study the effects of strain rate on the tensile strength of concrete. The influence of moisture content and compressive strength of concrete, and type of test (splitting tension, flexure, or direct tension) on the strain rate-sensitivity of the tensile strength were evaluated. An empirically developed expression is presented for the dynamic-to-static ratio of concrete tensile strength in terms of the rate of straining.

scholarly journals The Out-of-Plane Compression Response of Woven Thermoplastic Composites: Effects of Strain Rates and Temperature

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 264
Author(s):  
Shiyu Wang ◽  
Lihua Wen ◽  
Jinyou Xiao ◽  
Ming Lei ◽  
Xiao Hou ◽  
...  
Keyword(s):  
Strain Rate ◽  
Elevated Temperatures ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Dynamic Compression ◽  
Polyphenylene Sulfide ◽  
Thermoplastic Composites ◽  
Strain Rates ◽  
Wide Range ◽  
Out Of Plane

The dynamic mechanical response of high-performance thermoplastic composites over a wide range of strain rates is a challenging research topic for extreme environmental survivability in the field of aerospace engineering. This paper investigates the evolution of the dynamic properties of woven thermoplastic composites with strain rate and damage process at elevated temperatures. Out-of-plane dynamic-compression tests of glass-fiber (GF)- and carbon-fiber (CF)-reinforced polyphenylene sulfide (PPS) composites were performed using a split Hopkinson pressure bar (SHPB). Results showed that thermoplastic composites possess strain-rate strengthening effects and high-temperature weakening dependence. GF/PPS and CF/PPS composites had the same strain-rate sensitivity (SRS) below the threshold strain rate. The softening of the matrix at elevated temperatures decreased the modulus but had little effect on strength. Some empirical formulations, including strain-rate and temperature effects, are proposed for more accurately predicting the out-of-plane dynamic-compression behavior of thermoplastic composites. Lastly, the final failure of the specimens was examined by scanning electron microscopy (SEM) to explore potential failure mechanisms, such as fiber-bundle shear fracture at high strain rates and stretch break at elevated temperatures.

scholarly journals Experimental Study on Dynamic Compression Characteristics of Red Sandstone under Wetting-Drying Cycles

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bin Du ◽  
Haibo Bai ◽  
Minglei Zhai ◽  
Shixin He
Keyword(s):  
Compressive Strength ◽  
Fractal Dimension ◽  
Strain Rate ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Degradation Mechanism ◽  
Impact Compression ◽  
Red Sandstone ◽  
Dynamic Compressive Strength ◽  
The Impact

To study the influence of wetting-drying cycles on dynamic mechanical properties of rock masses, the impact compression tests of red sandstone samples were carried out by using a split Hopkinson pressure bar (SHPB) apparatus with a diameter of 50 mm. The results showed that under the same number of wetting-drying cycles, the dynamic compressive strength of red sandstone increased exponentially with the strain rate, and the sensitivity of the strain rate decreased with the increase of wetting-drying cycles. The deterioration effect of wetting-drying cycles was significant, and the dynamic and static compressive strength decreased with the increase of wetting-drying cycles; the higher the strain rate, the stronger the sensitivity to wetting-drying cycles. Besides, the influence of wetting-drying cycles and strain rate was comprehensively studied, and the equation of dynamic compressive strength of red sandstone was obtained. After different wetting-drying cycles, the fractal characteristics of red sandstone dynamic fragmentation were obvious, and the fractal dimension was 2.02–2.80, and the fractal dimension increased logarithmically with the strain rate. Finally, the internal microstructure of red sandstone after different wetting-drying cycles was analyzed, and the degradation mechanism of the rock by the cycles was discussed.

Age-Dependent Influence of Strain Rate on the Tensile Failure of Rat-Tail Tendon

1983 ◽  
Vol 105 (3) ◽  
pp. 296-299 ◽  
Author(s):  
R. C. Haut
Keyword(s):  
Tensile Strength ◽  
Energy Density ◽  
Connective Tissue ◽  
Strain Rate ◽  
Failure Strain ◽  
Tensile Failure ◽  
Strength Failure ◽  
Age Dependent ◽  
Tail Tendon ◽  
Rat Tail

Sensitivity of tensile strength, failure strain, and failure energy density to strain rate was studied for rat-tail tendon (RTT), a collagen-rich connective tissue. Tendons from animals aged 1–27 months were stretched at a high (720 percent/s) and low (3.6 percent/s) strain rate. Each failure parameter increased with strain rate. However, the sensitivity of tendon failure to rate of strain decreased rapidly during growth and sexual maturation of the animal. The study provides basic data on the rate-sensitive strength of collagen fibers using RTT.

Sign in / Sign up

Export Citation Format

Share Document