scholarly journals Inertial effect on concrete-like materials under dynamic direct tension

2018 ◽  
Vol 9 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Shu Zhang ◽  
Yubin Lu ◽  
Xiquan Jiang ◽  
Wei Jiang
Keyword(s):  
Tensile Strength ◽  
Dynamic Strength ◽  
Tensile Loading ◽  
Inertial Effect ◽  
Structural Effects ◽  
Direct Tension ◽  
Dynamic Tensile Strength ◽  
Strength Enhancement ◽  
Dynamic Tensile Loading ◽  
Tubular Specimens

The inertial effect on the dynamic strength enhancement of concrete-like materials has been widely concerned and its influence on the dynamic tensile strength is particularly controversial, causing great disturbance to dynamic measurement. Therefore, both the experimental and the numerical analyses on the tubular specimens of concrete-like materials are conducted to further investigate the degree of inertial effect under dynamic direct tension. The inertial effect is one of the structural effects, and therefore the tubular specimens with different inner diameters are employed to demonstrate the different influences of inertial effect on the dynamic tensile strength of concrete-like materials. The experimental and numerical results indicate that the inertial effect has some influence on dynamic tensile strength, which increases with strain rate. In addition, the surface area of concrete-like materials will be greatly affected by inertial effect under dynamic tensile loading.

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.

Dynamic Tensile Test of Coal, Shale and Sandstone Using Split Hopkinson Pressure Bar

2010 ◽  
Vol 1 (2) ◽  
pp. 24-37 ◽  
Author(s):  
Kaiwen Xia ◽  
Sheng Huang ◽  
Ajay Kumar Jha
Keyword(s):  
Tensile Strength ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Static Strength ◽  
Test Method ◽  
Hopkinson Pressure Bar ◽  
Dynamic Tensile Strength ◽  
Sandstone Sample ◽  
Rock Samples ◽  
Sandstone Rock

The dynamic tensile strength plays a pivotal role in rock fragmentation affecting the overall economics under the present ‘Mine to Mill Concept’. In this paper, a modified SHPB technique and Brazilian test method is presented to test the dynamic tensile strength of coal, shale and sandstone rock samples collected from three opencast mines of Coal India Limited and is compared with the static strength value. The dynamic tensile strength of coal and rock is much higher than static strength and tensile strength of coal and rock samples increase with loading rate. The result shows that the dynamic strength of the coal sample is 1.5 times higher than static strength and the dynamic strength of the sandstone sample is 3 times higher than the static strength.

Dynamic Tensile Test of Coal, Shale and Sandstone Using Split Hopkinson Pressure Bar

2012 ◽  
pp. 188-202
Author(s):  
Kaiwen Xia ◽  
Sheng Huang ◽  
Ajay Kumar Jha
Keyword(s):  
Tensile Strength ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Strength ◽  
Static Strength ◽  
Test Method ◽  
Hopkinson Pressure Bar ◽  
Dynamic Tensile Strength ◽  
Rock Samples ◽  
Split Hopkinson ◽  
Pressure Bar

The dynamic tensile strength plays a pivotal role in rock fragmentation affecting the overall economics under the present ‘Mine to Mill Concept’. In this paper, a modified SHPB technique and Brazilian test method is presented to test the dynamic tensile strength of coal, shale and sandstone rock samples collected from three opencast mines of Coal India Limited and is compared with the static strength value. The dynamic tensile strength of coal and rock is much higher than static strength and tensile strength of coal and rock samples increase with loading rate. The result shows that the dynamic strength of the coal sample is 1.5 times higher than static strength and the dynamic strength of the sandstone sample is 3 times higher than the static strength.

scholarly journals Enhancement Mechanism of the Dynamic Strength of Concrete Based on the Energy Principle

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1274 ◽  
Author(s):  
Jie Ren ◽  
Faning Dang ◽  
Huan Wang ◽  
Yi Xue ◽  
Jianyin Fang
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
Failure Process ◽  
Dynamic Strength ◽  
Peak Stress ◽  
Input Energy ◽  
Dynamic Tensile Strength ◽  
Enhancement Mechanism ◽  
Rates Of Change ◽  
Concrete Failure

This paper analyzes the relationship between the rates of change of elastic strain energy, the strength during the concrete failure process, and proposes that the increased dynamic strength of concrete was caused by the hysteresis effect of energy release—according to the basic principle of energy conversion. Dynamic Brazilian disc tests were carried out on concrete specimens, with diameter of 100 mm, by using the split Hopkinson pressure bar. Test results were obtained through using a gas gun, with an impact pressure of 0.15 MPa, 0.20 MPa and 0.25 MPa, respectively. The dynamic failure process of concrete is then reproduced by numerical calculation methods. Finally, the energy characteristics during the concrete failure process at different strain rates are studied, and the enhancement mechanism of the dynamic strength of concrete is verified. The results showed that the dynamic tensile strength of concrete increased by 9.79% when the strain rate increased by 61% from 60.25 s−1; and when the strain rate increased by 92.8% from 60.25 s−1, the dynamic tensile strength of the concrete rose by 46.28%. The rates of change of both input energy and dissipated energy meet at the peak stress of the material. The increases in rates of change for the two kinds of energy were not synchronized, so excess input energy could be stored as concrete strength increased. As a result, the extra energy stored after peak stress led to a higher degree of concrete fragmentation and greater kinetic energy of the fragment. These results offer research directions for improving the dynamic strength of concrete.

scholarly journals Spalling fracture mechanism of granite subjected to dynamic tensile loading

2021 ◽  
Vol 31 (7) ◽  
pp. 2116-2127
Author(s):  
Lin-qi HUANG ◽  
Jun WANG ◽  
Aliakbar MOMENI ◽  
Shao-feng WANG
Keyword(s):  
Fracture Mechanism ◽  
Tensile Loading ◽  
Spalling Fracture ◽  
Dynamic Tensile Loading

scholarly journals Dynamic Fracture Toughness and Dynamic Tensile Strength of the Rock from Different Depths of Beijing Datai Well

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Ke Man ◽  
Xiaoli Liu
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Dynamic Fracture ◽  
Empirical Relation ◽  
Dynamic Fracture Toughness ◽  
Rock Failure ◽  
Test Method ◽  
Strength Increase ◽  
Dynamic Tensile Strength ◽  
Different Depths

From the standard test method suggested by ISRM and GB/T50266-2013, the uniaxial static tensile strength, dynamic tensile strength, and dynamic fracture toughness of the same basalt at different depths have been measured, respectively. It is observed that there may be an empirical relation between dynamic fracture toughness and dynamic tensile strength. The testing data show that both the dynamic fracture toughness and dynamic tensile strength increase with the loading rate and the dynamic tensile strength increases a little bit more quickly than the dynamic fracture toughness. With an increasing depth, the dynamic tensile strength has much more influence on the dynamic fracture toughness, as which it is much liable to bring out the unexpected catastrophes in the engineering projects, especially during the excavation at deep mining. From the rock failure mechanisms, it is pointed out that the essential reason of the rock failure is the microcrack unstable propagation. The crack processes growth, propagation, and coalescence are induced by tensile stress, not shear stress or compressive stress. The paper provides estimation of the dynamic fracture toughness from the dynamic tensile strength value, which can be measured more easily.

scholarly journals Measurement of fracture energy of concrete at high strain rates

2018 ◽  
Vol 183 ◽  
pp. 02065
Author(s):  
V. Rey-de-Pedraza ◽  
F. Gálvez ◽  
D. Cendón Franco
Keyword(s):  
Tensile Strength ◽  
Fracture Energy ◽  
Dynamic Fracture ◽  
Dynamic Properties ◽  
Hopkinson Bar ◽  
Experimental Information ◽  
Tensile Fracture ◽  
Strain Rates ◽  
Dynamic Tensile Strength ◽  
Conventional Concrete

The Hopkinson Bar has been widely used by many researchers for the analysis of dynamic properties of different brittle materials and, due to its great interest, for the study of concrete. In concrete structures subjected to high velocity impacts, initial compression pulses travel through the material leading to tensile stresses when they reach a free surface. These tensile efforts are the main cause of concrete fracture due to its low tensile strength compared to the compressive one. This is the reason why dynamic tests in concrete are becoming of great interest and are mostly focused in obtaining tensile fracture properties. Apart form the dynamic tensile strength, which has been widely studied by many authors in the last decades, the dynamic fracture energy presents an increased difficulty and so not too much experimental information can be found in literature. Moreover, up to date there is not a clear methodology proposed in order to obtain this parameter in an accurate way. In this work a new methodology for measuring the dynamic fracture energy is proposed by using the Hopkinson Bar technique. Initial tests for a conventional concrete have been carried out and the results for the dynamic fracture energy of concrete at different strain rates are presented.

Maximum dynamic tensile strength of steel and method of determining IT

1979 ◽  
Vol 15 (2) ◽  
pp. 118-120
Author(s):  
D. A. Kal'ner ◽  
F. I. Basin
Keyword(s):  
Tensile Strength ◽  
Dynamic Tensile Strength
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