scholarly journals Impact performance of aluminium foams in a direct impact Hopkinson bar

2018 ◽  
Author(s):  
T. Cowie ◽  
C. W. A. Gurnham ◽  
C. H. Braithwaite ◽  
L. Lea
Keyword(s):  
Hopkinson Bar ◽  
Direct Impact ◽  
Impact Performance

scholarly journals Dynamic impact testing of cellular solids and lattice structures: Application of two-sided direct impact Hopkinson bar

2021 ◽  
Vol 148 ◽  
pp. 103767
Author(s):  
Tomáš Fíla ◽  
Petr Koudelka ◽  
Jan Falta ◽  
Petr Zlámal ◽  
Václav Rada ◽  
...  
Keyword(s):  
Hopkinson Bar ◽  
Impact Testing ◽  
Lattice Structures ◽  
Cellular Solids ◽  
Direct Impact ◽  
Dynamic Impact

Study on Preparation and Impact Performance of the Aluminium Foam Reinforced by ZrO2 Spheres

2011 ◽  
Vol 704-705 ◽  
pp. 1029-1034
Author(s):  
Jian Guo Wu ◽  
Lu Cai Wang
Keyword(s):  
High Hardness ◽  
Hopkinson Bar ◽  
Aluminium Foam ◽  
Composite Sample ◽  
Impact Performance ◽  
The Press

The aluminium foam can be reinforced by compositing high hardness ZrO2 ceramic spheres. On the condition of preparing the precursor composed of the salt particals and ceramic spheres, the sample of composite aluminium foam is parpared by the press casting infiltration process.By the Hopkinson Bar hopkinson bar experiment, the result shows the composite sample holded the better impact performance than the aluminium foam .All of these should establish a basement to promote the deeper study and developmenter of composite foamed material.

A New Experimental Technique to Characterize the Fiber Crush and Fiber Shear Behavior of Composites at Quasi-Static and High Rates of Strain

2006 ◽  
Author(s):  
Bazle A. Gama ◽  
John W. Gillespie
Keyword(s):  
Shear Test ◽  
Material Model ◽  
Hopkinson Bar ◽  
Test Method ◽  
Experimental Methodology ◽  
Direct Impact ◽  
Damage Behavior ◽  
Material Parameters ◽  
Test Methodology ◽  
Crush Strength

A new experimental method is developed to determine the fiber crush strength (SFC) and fiber shear strength (SFS) of composite materials following a punch shear test methodology. The material parameters SFC and SFS are used to model the damage behavior of thick-section composites as described in the LS-Dyna material model MAT_COMPOSITE_DMG_MSC, aka MAT162. The quasi-static experimental methodology is further extended to investigate the rate effect on SFS using a Hopkinson bar direct impact punch shear test method.

scholarly journals Deformation and fracture properties of pure ice through impact indentation testing

2021 ◽  
Vol 250 ◽  
pp. 06005
Author(s):  
Yuki Nakao ◽  
Hiroyuki Yamada ◽  
Nagahisa Ogasawara
Keyword(s):  
Indentation Test ◽  
Hopkinson Bar ◽  
Maximum Load ◽  
Direct Impact ◽  
Indentation Testing ◽  
Fracture Properties ◽  
Considerable Research ◽  
Deformation And Fracture ◽  
Static Indentation ◽  
The Impact

The deformation and fracture properties of ice have attracted considerable research interest. The tip shape of an object that comes into contact with the ice may affect the fracture phenomenon of ice, but these mechanisms have not been elucidated. In previous study, we experimentally showed that the shape of the indenter has a significant effect on pure ice deformation and fracture properties by quasi-static indentation testing. In this study, we focus on the impact fracture of pure ice to clarify the effect of strain rate on deformation and fracture phenomena. The impact indentation test was conducted using direct impact Hopkinson bar method, and a spherical indenter with a diameter of 9 mm was attached to the tip of the striking bar. The indentation rate was approximately 2.3 m/s, and the test temperature was approximately -10°C. It was clear that the maximum load of the load–displacement relationship was larger than that of the quasi-static indentation testing. This tendency was qualitatively consistent with the compressive strength of the uniaxial compression testing.

scholarly journals Investigating slow shock in low-impedance materials using a direct impact Hopkinson bar setup

2021 ◽  
Vol 250 ◽  
pp. 06009
Author(s):  
Puneeth Jakkula ◽  
Georg Ganzenmüller ◽  
Samuel Beisel ◽  
Stefan Hiermaier
Keyword(s):  
Dynamic Compression ◽  
Hopkinson Bar ◽  
Polyurethane Foams ◽  
Image Correlation ◽  
Dynamic Force ◽  
Strain Rates ◽  
Direct Impact ◽  
Compression Tests ◽  
Low Impedance Materials ◽  
Force Equilibrium

This work implements a direct impact Hopkinson bar, suitable for investigating the evolution of dynamic force equilibrium in low-impedance materials. Polycarbonate as the bar material favours for a long pulse duration of 2.6 ms for an overall length of only 5 m, allowing to compress large specimens to high strains. This setup is applied to polyurethane foams with different densities ranging from 80 - 240 kg/m3. Dynamic compression tests are performed at strain rates of 0.0017, 0.5 and 500 /s on the foams at room temperature. Depending on density, they show a saturation in increase of yield strength at strain rates of 500 /s, or even show a negative strain rate sensitivity for the lowest density. This behaviour is explained by comparing the dynamic force equilibrium to a phenomenon similar to shock in solid materials: For low densities and high rates of strain, homogeneous compression is replaced by a localized collapse front with a jump in stress across the front. Digital image correlation is performed to analyse elastic and plastic compaction waves by means of Lagrange diagrams.

Study on Impact Protection Properties of Titanium Alloy Using Modified SHPB

2013 ◽  
Vol 302 ◽  
pp. 14-19 ◽  
Author(s):  
Jie Liu ◽  
Jin Xu Liu ◽  
Hong Sheng Ding ◽  
Shu Kui Li ◽  
Yu Meng Luo
Keyword(s):  
Impact Velocity ◽  
Loading Condition ◽  
Hopkinson Bar ◽  
Impact Testing ◽  
Direct Impact ◽  
Protective Properties ◽  
Impact Protection ◽  
Protective Performance ◽  
The Impact ◽  
Modified Hopkinson Bar

In order to evaluate the impact protection capacity of armor material quantitatively, direct impact testing loaded by modified Hopkinson bar was used to simulate the impaction between penetrator and armor. Protection coefficient k was defined to describe the protective performance. Using the direct impact testing, Ti-6Al-4V specimens with different microstructure and thickness were tested. Results show that k decreases with increased impact velocity and increases with increased thickness of specimen. Under a given loading condition, binary microstructure exhibits the highest k, indicating the best protective performance. Moreover, its k shows the most sensitivity to thickness (mt) and the least sensitivity to impact energy (me), which means that its protective performance can be improved most efficiently by increasing its thickness and it will exhibit good protective performance in a wider impact velocity range. This new method can evaluate the impact protective properties of armor materials efficiently, which may have a broad application prospect.

Infrastructure mortgage in Russia: Opportunities and prospects

2019 ◽  
pp. 114-133
Author(s):  
G. I. Idrisov ◽  
Y. Yu. Ponomarev
Keyword(s):  
Federal Government ◽  
Public Debt ◽  
Budget Deficit ◽  
Expert Assessment ◽  
Inflation Expectations ◽  
Direct Impact ◽  
Long Run ◽  
Gdp Growth Rate ◽  
Negative Effect

The article shows that depending on the goals pursued by the federal government and the available interbudgetary tools a different design of infrastructure mortgage is preferable. Three variants of such mortgage in Russia are proposed, each of which is better suited for certain types of projects and uses different forms of subsidies. According to our expert assessment the active use of infrastructure mortgage in Russia can increase the average annual GDP growth rate by 0.5 p. p. on the horizon of 5—7 years. In the long run the growth of infrastructure financing through the use of infrastructure mortgage could increase long-term economic growth by 0.9 p. p., which in 20—30 years can add 20—30% of GDP to the economy. However, the change in the structure of budget expenditures in the absence of an increase in the budget deficit and public debt will cause no direct impact on monetary policy. The increase in the deficit and the build-up of public debt will have a negative effect on inflation expectations, which will require monetary tightening for a longer time to stabilize them.

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