scholarly journals Research on Dynamic Mechanical Properties and Constitutive Model of Basalt Fiber Reinforced Concrete after Exposure to Elevated Temperatures under Impact Loading

2020 ◽  
Vol 10 (21) ◽  
pp. 7684
Author(s):  
Wenbiao Liang ◽  
Junhai Zhao ◽  
Yan Li ◽  
Yue Zhai ◽  
Zhou Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Basalt Fiber ◽  
Peak Stress ◽  
Confining Pressure ◽  
Dynamic Mechanical Properties ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Dynamic Mechanical ◽  
Different Temperatures

The dynamic mechanical properties of basalt fiber reinforced concrete (BFRC) with different fiber contents (0.0%, 0.1%, 0.2%, 0.3%, 0.4%), confining pressures (0 MPa, 5 MPa, 10 MPa, 15 MPa) and exposed to different temperatures (20 °C, 200 °C, 400 °C, 600 °C, 800 °C) were investigated by using a 50 mm split Hopkinson pressure bar (SHPB) apparatus, and the factors such as fiber content, temperature and confining pressure effect on the dynamic mechanical properties were analyzed. The results show that the dynamic peak stress increases first and then decreases with the increase of fiber content. At different temperatures, the peak stress and its corresponding strain correspond to different fiber content, and the optimal fiber content is between 0.1% and 0.3%. When the temperature was from 20 °C to 400 °C, the dynamic peak stress decreased less, while when the temperature reached 600 °C and 800 °C, the dynamic peak stress decreased greatly. The confining pressure can significantly increase the dynamic peak stress and change the crushing morphology of specimens. The damage variable was built based on the Weibull distribution. A dynamic damage constitutive model combining statistical damage and viscoelastic model was established based on component combination model. The fitting curve of this model fitted well with test curve by identifying fewer undetermined parameters compared with Zhu-Wang-Tang (ZWT) model; therefore, this model can well describe the dynamic properties of BFRC under impact load.

scholarly journals Study on Dynamic Mechanical Properties and Constitutive Model Construction of TC18 Titanium Alloy

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 44 ◽  
Author(s):  
Changming Zhang ◽  
Anle Mu ◽  
Yun Wang ◽  
Hui Zhang
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Flow Stress ◽  
Yield Strength ◽  
Constitutive Model ◽  
Testing Machine ◽  
Dynamic Mechanical Properties ◽  
Stress Strain ◽  
Dynamic Mechanical ◽  
Different Temperatures

In order to investigate the static and dynamic mechanical properties of TC18 titanium alloy, the quasi-static stress–strain curve of TC18 titanium alloy under room temperature was obtained by DNS 100 electronic universal testing machine (Changchun Institute of Mechanical Science Co., Ltd., Changchun, China). Meanwhile, the flow stress–strain curves under different temperatures and strain rates are analyzed by split Hopkinson pressure bar (SHPB) device with synchronous assembly system. On the basis of the two experimental data, the JC constitutive model under the combined action of high temperature and impact load is established using the linear least squares method. The results show the following: the yield strength and flow stress of TC18 titanium alloy increase slowly with the increase of the strain rate, and the strain value corresponding to the yield strength is reduced. With the increase of strain, the flow stress increases at first and then decreases at different temperatures. The strain value corresponding to the transition point rises with the temperature increase, and the corresponding stress value remains basically unchanged. With the increase of experimental temperature, the flow stress shows a downward trend, and the JC constitutive model can predict the plastic flow stress well.

scholarly journals SHPB Testing and Analysis of Bedded Shale under Active Confining Pressure

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Guoliang Yang ◽  
Jingjiu Bi ◽  
Xuguang Li ◽  
Jie Liu ◽  
Yanjie Feng
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Peak Stress ◽  
Confining Pressure ◽  
Dynamic Mechanical Properties ◽  
Dynamic Elastic Modulus ◽  
Peak Strain ◽  
Dynamic Mechanical ◽  
Bedding Angle

Shale gas is the most important new energy source in the field of energy, and its exploitation is very important. The research on the dynamic mechanical properties of shale is the premise of exploitation. To study the dynamic mechanical properties of shale from the Changning-Weiyuan area of Sichuan Province, China, under confining pressure, we used a split Hopkinson pressure bar (SHPB) test system with an active containment device to carry out dynamic compression tests on shale with different bedding angles. (1) With active confining pressure, the shale experiences a high strain rate, and its stress-strain curve exhibits obvious plastic deformation. (2) For the same impact pressure, the peak stress of shale describes a U-shaped curve with an increasing bedding angle; besides, the peak stress of shale with different bedding angles increases linearly with rising confining pressure. The strain rate shows a significant confining pressure enhancement effect. With active confining pressure, the peak strain gradually decreases as the bedding angle increases. (3) As a result of the influence of different bedding angles, the dynamic elastic modulus of shale has obvious anisotropic characteristics. Shale with different bedding angles exhibits different rates of increase in the dynamic elastic modulus with rising confining pressure, which may be related to differences in the development of planes of weakness in the shale. The results of this study improve our understanding of the behavior of bedded shale under stress.

scholarly journals Effect of Basalt Fiber on Static and Dynamic Mechanical Properties of Metakaolin-Based Cement Clay

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Kun Huang ◽  
Qinyong Ma ◽  
Dongdong Ma
Keyword(s):  
Mechanical Properties ◽  
Basalt Fiber ◽  
Deformation Modulus ◽  
Strain Curve ◽  
Peak Stress ◽  
Dynamic Mechanical Properties ◽  
Fiber Content ◽  
Test Results ◽  
Stress Strain ◽  
Reinforcement Mechanism

To investigate the effects of basalt fiber content on the mechanical properties and microstructure characteristic of metakaolin-based cement clay, the static and dynamic uniaxial compressive and splitting tensile, nuclear magnetic resonance (NMR), and scanning electron microscope (SEM) tests were performed to study the stress-strain curves, static and dynamic peak stress, pore distribution characteristic, and reinforcement mechanism. In this research, the basalt fiber with the length of 12 mm were selected and the ratios between fiber and dry soil were 0%, 0.5%, 1.0%, 1.5%, and 2.0%, respectively. The obtained results showed a noticeable difference of stress-strain curve characteristics in the static and dynamic compressive tests. A positive correlation between deformation modulus and compressive strength was found for both static and dynamic tests. The addition of basalt fiber could efficiently increase the static and dynamic strengths of metakaolin-based cement clay, and the increment 66.15% and 74.63% was observed at 1.0% basalt fiber content for static and dynamic compressive strengths, respectively, while the corresponding increment values were 93.75% and 97.62% for its splitting tensile strengths, respectively. The basalt fiber could decrease the porosity of cement clay; moreover, the reinforcement mechanism of metakaolin and basalt fiber to cement clay was analyzed based on the SEM test results.

Dynamic mechanical properties of hybrid fiber reinforced concrete

2022 ◽  
pp. 204141962110654
Author(s):  
Yong Zhang ◽  
Li Chen ◽  
Dong-lei Zhou
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Failure Mode ◽  
Dynamic Mechanical Properties ◽  
Fiber Content ◽  
Fiber Reinforced Concrete ◽  
Peak Strain ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Dynamic Mechanical

In this study, the dynamic mechanical properties of hybrid fiber reinforced concrete (HFRC) are analyzed with respect to failure mode, dynamic increase factor (DIF), and peak strain by means of a SHPB testing apparatus. The factors that influence the dynamic mechanical properties include fiber type and fiber content. It is concluded that the best dynamic mechanical properties of fibers are CS-PHFRC at medium and low strain rates and AS-PHFRC at a high strain rate. Within a certain range, the higher the fiber content is, the larger the DIF of the corresponding HFRC and the more obvious the increase in dynamic compressive strength. AS-CSHFRC improves the dynamic compressive deformability of the HFRC. The polypropylene fiber causes plasticity, as shown in the failure mode of concrete. The Ottosen nonlinear elastic model, modified by introducing the damage factor, can better describe the dynamic mechanical properties of HFRC.

scholarly journals Effect of Basalt Fiber Addition on Static-Dynamic Mechanical Behaviors and Microstructure of Stabilized Soil Compositing Cement and Fly Ash

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Ziming Cao ◽  
Qinyong Ma ◽  
Hongwei Wang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Unconfined Compressive Strength ◽  
Basalt Fiber ◽  
Dynamic Mechanical Properties ◽  
Fiber Content ◽  
Dynamic Mechanical ◽  
Stabilized Soil ◽  
Dynamic Compressive Strength

The purpose of this article is to evaluate the influence of basalt fiber content on the static-dynamic mechanical properties and microstructure of cement-fly ash-stabilized soil. The optimum mixed contents of cement and fly ash were obtained from the results of a series of physical and mechanical experiments. Based on the optimum mixed contents of cement and fly ash, the static-dynamic mechanical performances and microstructure of cement-fly ash-stabilized soil reinforced with basalt fiber were studied by means of the unconfined compression test, dynamic compression test (namely, SHPB test), and SEM test. The results demonstrated that the addition of basalt fiber in cement-fly ash-stabilized soil significantly enhanced the static-dynamic mechanical properties of stabilized soil. With basalt fiber content varying from 0% to 1.2%, the unconfined compressive strength, dynamic compressive strength, dynamic increase factor, and specific energy absorption of stabilized soil showed an upward trend first and a downward trend subsequently. The unconfined compressive strength, dynamic compressive strength, and energy absorption ability have a maximum improvement under the optimum basalt fiber content of 0.6%. In addition, the inclusion of basalt fiber can change the failure pattern of cement-fly ash-stabilized soil. The fractal dimension of broken fragments decreased gradually with the increasing basalt fiber content and increased correspondingly with the increasing impact loading pressure. With the basalt fiber content of 0.6%, a stable internal space structure produced inside stabilized soil. However, there are many fiber-fiber weak interfaces that appeared inside stabilized soil under the basalt fiber content of 1.2%. The microstructural observations can be considered as the good interpretations to verify the macroscopic mechanical characteristics.

scholarly journals Effect of Short Fiber Reinforcement on Mechanical Properties of Hybrid Phenolic Composites

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Sembian Manoharan ◽  
Bhimappa Suresha ◽  
Govindarajulu Ramadoss ◽  
Basavaraj Bharath
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Loss Modulus ◽  
Basalt Fiber ◽  
Barium Sulphate ◽  
Dynamic Mechanical Properties ◽  
Damping Factor ◽  
X Ray ◽  
Weight Percentage ◽  
Dynamic Mechanical

Fiber plays an important role in determining the hardness, strength, and dynamic mechanical properties of composite material. In the present work, enhancement of viscoelastic behaviour of hybrid phenolic composites has been synergistically investigated. Five different phenolic composites, namely, C1, C2, C3, C4, and C5, were fabricated by varying the weight percentage of basalt and aramid fiber, namely, 25, 20, 15, 10, and 5% by compensating with barium sulphate (BaSO4) to keep the combined reinforcement concentration at 25 wt%. Hardness was measured to examine the resistance of composites to indentation. The hardness of phenolic composites increased from 72.2 to 85.2 with increase in basalt fiber loading. Composite C1 (25 wt% fiber) is 1.2 times harder than composite C5. Compression test was conducted to find out compressive strength of phenolic composites and compressive strength increased with increase in fiber content. Dynamic mechanical analysis (DMA) was carried out to assess the temperature dependence mechanical properties in terms of storage modulus (E′), loss modulus (E′′), and damping factor (tan δ). The results indicate great improvement of E′ values and decrease in damping behaviour of composite upon fiber addition. Further X-ray powder diffraction (XRD) and energy-dispersive X-ray (EDX) analysis were employed to characterize the friction composites.

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