Evaluation of Friction at High Strain Rate using the Split Hopkinson Bar

2015 ◽  
Vol 651-653 ◽  
pp. 108-113 ◽  
Author(s):  
Archimede Forcellese ◽  
Edoardo Mancini ◽  
Marco Sasso ◽  
Michela Simoncini
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strain ◽  
Outer Diameter ◽  
Loading Conditions ◽  
Split Hopkinson ◽  
Dynamic Loading Conditions ◽  
Static And Dynamic Loading ◽  
Frictional Behaviour

The present work aims at studying the influence of strain rate on the frictional behaviour of AA7075 aluminium alloy in the O-annealed temper state. To this purpose, ring compression tests were performed both under quasi-static and dynamic loading conditions. The high strain rate tests were carried out by means of the Split Hopkinson Tension-Compression Bar in the direct version. In both cases, hollow cylindrical samples, characterised by an initial outer diameter to inner diameter to height ratio of 6:3:2, were tested under dry condition and by lubricating with molybdenum disulphide grease. The different frictional behaviour exhibited by AA7075-O under quasi-static and dynamic loading conditions can be attributed to the strain rate effect both on the plastic flow behaviour of the deformed material, and on the thickness of the lubricant film.

High Strain Rate Response of Rocks Under Dynamic Loading Using Split Hopkinson Pressure Bar

2017 ◽  
Vol 36 (1) ◽  
pp. 531-549 ◽  
Author(s):  
Sunita Mishra ◽  
Hemant Meena ◽  
Vedant Parashar ◽  
Anuradha Khetwal ◽  
Tanusree Chakraborty ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar

Dynamic fracture under impact and high-strain-rate loading

1995 ◽  
Vol 73 (5-6) ◽  
pp. 315-323 ◽  
Author(s):  
M. J. Worswick ◽  
J. A. Clarke ◽  
R. J. Pick
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Ductile Fracture ◽  
Damage Evolution ◽  
High Strain ◽  
Yield Criterion ◽  
Damage And Fracture ◽  
Split Hopkinson ◽  
Strain Rate Loading ◽  
Dynamic Loading Conditions

A constitutive model based on a pressure-dependent yield criterion is used to predict damage evolution and ductile fracture under dynamic loading conditions. The model predicts the influence of porosity on plastic flow in metals and the nucleation, growth, and coalescence of internal microvoids to cause ductile fracture. The constitutive equations have been implemented in the DYNA2D finite-element code and have been used to simulate three high-strain-rate experiments: (i) the symmetric Taylor cylinder impact, (ii) the plate impact, and (iii) the tensile split Hopkinson bar experiments. In each case, the model is shown to capture qualitatively the damage and fracture within the experiments modelled. Comparison with recent symmetric Taylor impact experiments on leaded brass suggests that the model over-predicts the rate of damage evolution under the high-strain rate, high-triaxiality conditions associated with impact.

Changing the Hardness Automotive Steels at Different Strain Rate

2014 ◽  
Vol 635 ◽  
pp. 41-44
Author(s):  
Miroslav Német ◽  
Mária Mihaliková ◽  
Alexandra Kovalčíkova ◽  
Anna Lišková
Keyword(s):  
Strain Rate ◽  
Dynamic Loading ◽  
Automotive Industry ◽  
Interstitial Free ◽  
Loading Conditions ◽  
Product Testing ◽  
Dynamic Conditions ◽  
Interstitial Free Steel ◽  
Dynamic Loading Conditions ◽  
Static And Dynamic Loading

Currently, the automotive industry used sheets of different qualities. The most common include IF (inter Interstitial Free) steel and alloyed steel. Use the sheet quality depends on the point of application in the production car. Testing and product testing is a standard part of the process of innovation and production itself. Testing of automotive steels under dynamic conditions is increasingly important. Changing the hardness HV 1 was performed on the fractured bars on the static and dynamic loading conditions. Tests were made on steel IF and S 460.

High Strain-Rate Compressive Response of Epoxy Composites

2012 ◽  
Vol 217-219 ◽  
pp. 138-141
Author(s):  
Hai Xia Hu ◽  
Zhao Zheng Liu ◽  
Wei Dong Liu
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Performance ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Epoxy Composites ◽  
Hopkinson Pressure Bar ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Dynamic Loading Conditions

The high strain rate compressive behavior of a bicomponent high performance epoxy resin for advanced composites filled with Polyaryletherketone (PAEK) has been studied on a modified split Hopkinson Pressure Bar (SHPB) setup under dynamic loading conditions. Dynamic stress-strain plot was obtained for each sample. The results of the study indicated that the plastic of the epoxy composites increased while yield strength decreases slightly with the increase of the content of PAEK powder. In contrast, EP/PAEK-10 composite has the best Compressive properties.

Dynamic Behaviors of near β-Type Ti-5Al-5Mo-5V-3Cr Titanium Alloys under High Strain Rate

2015 ◽  
Vol 816 ◽  
pp. 795-803
Author(s):  
Yan Ling Wang ◽  
Song Xiao Hui ◽  
Wen Jun Ye ◽  
Rui Liu
Keyword(s):  
Strain Rate ◽  
Titanium Alloys ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Failure Behavior ◽  
Hopkinson Pressure Bar ◽  
Fracture Failure ◽  
Split Hopkinson ◽  
Pressure Bar ◽  
Dynamic Loading Conditions

The mechanical properties and fracture failure behavior of the near β-type Ti-5Al-5Mo-5V-3Cr-X (X = 1Fe or 1Zr) titanium alloys were studied by Split Hopkinson Pressure Bar (SHPB) experiment under the dynamic loading conditions at a strain rate of 1.5 × 103 s-1–5.0 × 103 s-1. Results showed that the SHPB specimen fractured in the direction of maximum shearing stress at an angle of 45° with the compression axis. The fracture surface revealed the shear and tension zones with cleavage steps and parabolic dimples. Severe early unloading was observed on the Ti-5553 alloy under a strain rate of 4,900 s-1 loading condition, and the dynamic property of the Ti-55531Zr alloy was proved to be the optimal.

scholarly journals Rate-dependent ductile fracture under plane strain tension: experiments and simulations

2018 ◽  
Vol 183 ◽  
pp. 02022
Author(s):  
Vincent Grolleau ◽  
Vincent Lafilé ◽  
Christian C. Roth ◽  
Bertrand Galpin ◽  
Laurent Mahéo ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Plane Strain ◽  
Static Loading ◽  
High Strain ◽  
Fracture Initiation ◽  
Surface Strain ◽  
Experimental Program ◽  
Loading Conditions ◽  
Plane Strain Tension

Among all other stress states achievable under plane stress conditions, the lowest ductility is consistently observed for plane strain tension. For static loading conditions, V-bending of small sheet coupons is the most reliable way of characterising the strain to fracture for plane strain tension. Different from conventional notched tension specimens, necking is suppressed during V-bending which results in a remarkably constant stress state all the way until fracture initiation. The present DYMAT talk is concerned with the extension of the V-bending technique from low to high strain rate experiments. A new technique is designed with the help of finite element simulations. It makes use of modified Nakazima specimens that are subjected to V-bending. Irrespective of the loading velocity, plane strain tension conditions are maintained throughout the entire loading history up to fracture initiation. Experiments are performed on specimens extracted from aluminum 2024-T3 and dual phase DP450 steel sheets. The experimental program includes quasi static loading conditions which are achieved on a universal testing machine. In addition, high strain rate experiments are performed using a specially-designed drop tower system. In all experiments, images are acquired with two cameras to determine the surface strain history through stereo Digital Image Correlation (DIC). The experimental observations are discussed in detail and also compared with the numerical simulations to validate the proposed experimental technique

Tensile Ductility of Ultra-Fine Grained Copper at High Strain Rate

2010 ◽  
Vol 160-162 ◽  
pp. 260-266 ◽  
Author(s):  
Tao Suo ◽  
Kui Xie ◽  
Yu Long Li ◽  
Feng Zhao ◽  
Qiong Deng
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Testing Machine ◽  
Coarse Grained ◽  
Dislocation Dynamic ◽  
Pressing Method ◽  
Fine Grained ◽  
Angular Pressing ◽  
Split Hopkinson

In this paper, ultra-fine grained copper fabricated by equal channel angular pressing method and annealed coarse grained copper were tensioned under both quasi-static and dynamic loading conditions using an electronic universal testing machine and the split Hopkinson tension bar respectively. The rapture surface of specimen was also observed via a Scanning Electron Microscope (SEM). The experimental results show that the ductility of polycrystalline copper decreases remarkably due to the grain refinement. However, with the increase of applied strain rate, ductility of the UFG-Cu is enhanced. The fracture morphologies also give the evidence of enhanced ductility of UFG-Cu at high strain rate. It is believed the enhanced ductility of UFG materials at high strain rate can be attributed to the restrained dislocation dynamic recovery.

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