scholarly journals Study on Dynamic Mechanical Properties of Limestone under Uniaxial Impact Compressive Loads

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Fei Zou ◽  
Zheng-feng Fang ◽  
Ming-yao Xia
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Failure Modes ◽  
Constant Strain Rate ◽  
Reference Value ◽  
Axial Direction ◽  
Dynamic Mechanical Properties ◽  
Impact Pressure ◽  
Pulse Shaper ◽  
Dynamic Mechanical

The dynamic mechanical properties of limestone are studied with 5 types of impact pressure acting on limestone samples in axial direction in this paper. The rubber shaper with a diameter of 5 mm and thickness of 2 mm is adopted. Besides the conical punch of split pressure bar of Hopkinson with a diameter of 50 mm is also used. The half-sinusoid pulse is obtained by using the pulse shaper method and special punch method; the constant strain rate deformation of the sample is realized. Dynamic compressive properties and failure modes of limestone under different impact pressure are investigated. In addition, energy dissipation is studied in the process of experiment. The results show that the dynamic compressive strength of limestone has an exponent relation to strain rate. The failure strain, degree of fragmentation, incident energy, and absorption energy increase, while the energy absorbency decreases with the increasing of strain rate. However, the initial elastic modulus is not sensitive to the strain rate. The research method and conclusions have reference value for the dynamic mechanical properties of other brittle materials.

Experimental Study on Dynamic Mechanical Properties of Amphibolites, Sericite-quartz Schist and Sandstone under Impact Loadings

2012 ◽  
Vol 13 (2) ◽  
pp. 209-217
Author(s):  
Jun-Zhong Liu ◽  
Jin-Yu Xu ◽  
Xiao-Cong Lv ◽  
De-Hui Zhao ◽  
Bing-Lin Leng
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Failure Mode ◽  
Failure Modes ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Mechanical Properties ◽  
Tensile Failure ◽  
Strength Increase ◽  
Dynamic Mechanical ◽  
Rock Samples

Abstract In order to investigate rock dynamic mechanical properties of amphibolites, sericite-quartz schist and sandstone under the different strain rates varying from 30 s -1 to 150 s -1 , the specimens were subjected to axial impact at different projectile speeds by using the split Hopkinson pressure bar (SHPB) of 100 mm in diameter. The optimal experimental size of rock samples is verified by analyzing the stress equilibrium of cylindrical rock samples in different thicknesses. It has studied the mechanic properties of these three rocks which under impact loadings; and analysed the dynamic compressive strength, failure modes, energy dissipation variation with the strain-rate and the strain-rate hardening effect from the perspective of material microstructure. Experimental results show that the dynamic Young's modulus of rock samples increase with strain-rate slightly. The dynamic failure modes of different rock samples are always different. When at a lower strain-rate, the damage of sandstone takes a peeling off the external radial tensile failure mode, but that of amphibolites takes axial splitting mode; when at a higher strain-rate, sandstone takes granular crushing failure mode, and that of amphibolites and of sericite-quartz schist take massive crushing mode. Significant strain-rate effect can be represented by a linear relation between the specific energy absorption and the strain-rate , or between the dynamic strength increase factor η and .

Effect of Graphene Nanoplatelets Content on Dynamic Mechanical Property of GNPs/Ti Composites

2018 ◽  
Vol 910 ◽  
pp. 123-129 ◽  
Author(s):  
X.N. Mu ◽  
H.N. Cai ◽  
Hong Mei Zhang ◽  
Q.B. Fan ◽  
Y. Wu
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Stress ◽  
Dynamic Compression ◽  
Dynamic Mechanical Properties ◽  
Graphene Nanoplatelets ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Dynamic Mechanical ◽  
Adiabatic Shearing

In this study, the titanium matrix composites (TiMCs) were fabricated by adding graphene nanoplatelets (GNPs). The dynamic compression test was carried out to study the effect of strain-rate and the GNPs content on dynamic mechanical properties of GNPs/Ti. Results show that the GNPs content (0wt%~0.8wt%) correspond to specific microstructure which affect the dynamic mechanical properties of the composites. Under high strain-rate (3500s-1), the 0.4wt%GNPs/Ti has the highest dynamic stress (~1860MPa) and strain (~30%). The adiabatic shearing band (ASB) microstructure of GNPs/Ti with various GNPs content has been observed under 3500s-1 strain-rate and the ASB microstructure evolution of 0.4wt%GNPs/Ti under different strain rate was investigated in particular.

scholarly journals Dynamic Mechanical Properties and Microstructure of an (Al0.5CoCrFeNi)0.95Mo0.025C0.025 High Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (12) ◽  
pp. 1154
Author(s):  
Bingfeng Wang ◽  
Chu Wang ◽  
Bin Liu ◽  
Xiaoyong Zhang
Keyword(s):  
Mechanical Properties ◽  
Shear Band ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Dynamic Mechanical Properties ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Dynamic Mechanical

The dynamic mechanical properties and microstructure of the (Al0.5CoCrFeNi)0.95Mo0.025C0.025 high entropy alloy (HEA) prepared by powder extrusion were investigated by a split Hopkinson pressure bar and electron probe microanalyzer and scanning electron microscope. The (Al0.5CoCrFeNi)0.95Mo0.025C0.025 HEA has a uniform face-centered cubic plus body-centered cubic solid solution structure and a fine grain-sized microstructure with a size of about 2 microns. The HEA possesses an excellent strain hardening rate and high strain rate sensitivity at a high strain rate. The Johnson–Cook plastic model was used to describe the dynamic flow behavior. Hat-shaped specimens with different nominal strain levels were used to investigate forced shear localization. After dynamic deformation, a thin and short shear band was generated in the designed shear zone and then the specimen quickly fractured along the shear band.

scholarly journals Dynamic Mechanical Compression Impulse of Lithium-Ion Pouch Cells

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2105 ◽  
Author(s):  
Alon Ratner ◽  
Richard Beaumont ◽  
Iain Masters
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Lithium Ion ◽  
Rate Sensitivity ◽  
Dynamic Mechanical Properties ◽  
Impact Testing ◽  
Significant Feature ◽  
Dynamic Mechanical ◽  
The Impact

Strain rate sensitivity has been widely recognized as a significant feature of the dynamic mechanical properties of lithium-ion cells, which are important for their accurate representation in automotive crash simulations. This research sought to improve the precision with which dynamic mechanical properties can be determined from drop tower impact testing through the use of a diaphragm to minimize transient shock loads and to constrain off-axis motion of the indenter, specialized impact absorbers to reduce noise, and observation of displacement with a high speed camera. Inert pouch cells showed strain rate sensitivity in an increased stiffness during impact tests that was consistent with the poromechanical interaction of the porous structure of the jellyroll with the liquid electrolyte. The impact behaviour of the inert pouch cells was similar to that of an Expanded Polypropylene foam (EPP), with the exception that the inert pouch cells did not show hysteretic recovery under the weight of the indenter. This suggests that the dynamic mechanical behaviour of the inert pouch cells is analogous to a highly damped foam.

The Dynamic Mechanical Properties of CBF Composite Plate and its Sandwich Structure with Aluminum Foam Core

2010 ◽  
Vol 452-453 ◽  
pp. 281-284
Author(s):  
Zhong Liang Chang ◽  
Guang Ping Zou ◽  
Wei Ling Zhao ◽  
Yang Cao ◽  
Rui Rui Wang
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Composite Plate ◽  
Sandwich Structure ◽  
Aluminum Foam ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Mechanical Properties ◽  
Alkali Resistance ◽  
Foam Core ◽  
Dynamic Mechanical

The continuous basalt fiber (CBF) as inorganic fiber obtained from the basalt melt. It has high elastic modulus, low bulk density, low thermal conductivity, low moisture absorption rate and excellent alkali resistance, etc. In this paper, the split Hopkinson pressure bar (SHPB) technique is used for testing the CBF composite plate and its sandwich structure with aluminum foam core dynamic mechanical properties, and then to study the dynamic properties of CBF composite plate and its aluminum foam sandwich structure under different high strain rate. From the test results we can see that the CBF-foam aluminum sandwich structure has superior energy absorption properties, and also from the experiment results we can obtain that the sandwich structure dynamic stress-strain curves has a typically "three-phase" characteristics and strain rate effect.

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