scholarly journals Damage detection versus heat dissipation in E-glass/Epoxy laminated composites under dynamic compression at high strain rate

2018 ◽  
Vol 186 ◽  
pp. 50-61 ◽  
Author(s):  
M. Tarfaoui ◽  
A. El Moumen ◽  
H. Ben Yahia
Keyword(s):  
High Strain Rate ◽  
Damage Detection ◽  
Strain Rate ◽  
Heat Dissipation ◽  
High Strain ◽  
Laminated Composites ◽  
Dynamic Compression

Thermomechanical behavior of adhesively bonded joints under out-of-plane dynamic compression loading at high strain rate

2018 ◽  
Vol 52 (30) ◽  
pp. 4171-4184 ◽  
Author(s):  
Sonia Sassi ◽  
M Tarfaoui ◽  
Hamza B Yahia
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Heat Dissipation ◽  
High Strain ◽  
Dynamic Compression ◽  
Bonded Joints ◽  
Loading Conditions ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Out Of Plane

In this study, a new experimental approach in which the deformation, the damage kinetic, and the temperature are measured simultaneously during a high strain rate on adhesively bonded composite joints. Especially, our goal is to quantify the amount heat dissipation during impact and to identify the mechanisms that induce this dissipation. Out of plane dynamic compression tests were conducted on assembled specimens over a range of strain rate from 372 s−1 to 1030 s−1 using the Split hopkinson Pressure Bars technique. The specimen surface temperatures were monitored using an infrared camera. The increase in the strain rate has a dramatic effect on the stress–strain behavior producing a significant heat dissipation in the material. The infrared monitoring provides the spatial distribution of temperature that increase near the adhesive/adherent interfaces of the specimen. The observed temperature increase profiles clearly show that the stress concentration appears in the adhesive area and provide valuable information regarding the damage mechanisms and their role in the heat dissipation during dynamic loading conditions. The dependence of these results on strain rate indicates that there exists a correlation between the thermo-mechanical behavior and the strain rate effect, which might be useful when developping damage models taking into account the energy balance for adhesively bonded joints under impact loading conditions.

scholarly journals High strain rate behaviour of fiber reinforced concrete

2018 ◽  
Vol 183 ◽  
pp. 02012
Author(s):  
Miloslav Popovič ◽  
Jaroslav Buchar ◽  
Martina Drdlová
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Fiber Reinforced Concrete ◽  
Hopkinson Pressure Bar ◽  
Static Test ◽  
Pressure Bar

The results of dynamic compression and tensile-splitting tests of concrete reinforced by randomly distributed short non – metallic fibres are presented. A Split Hopkinson Pressure Bar combined with a high-speed photographic system, was used to conduct dynamic Brazilian tests. Quasi static test show that the reinforcement of concrete by the non-metallic fibres leads to the improvement of mechanical properties at quasi static loading. This phenomenon was not observed at the high strain rate loading .Some explanation of this result is briefly outlined.

Effects of Impressed-Current on Sensitivity of Adiabatic Shear of TC6 Titanium Alloy

2013 ◽  
Vol 718-720 ◽  
pp. 107-111
Author(s):  
Kun Sun ◽  
Kai Hua Yue ◽  
Yuan Xu ◽  
Wen Li Xiang ◽  
Wei Zhong
Keyword(s):  
Titanium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Room Temperature ◽  
High Strain ◽  
Adiabatic Shear Band ◽  
Dynamic Compression ◽  
Adiabatic Shear ◽  
Split Hopkinson ◽  
Impressed Current

Dynamic compression test on TC6 titanium alloy samples have been done by using a split Hopkinson bar process and extra circuit under conditions of room temperature and high strain-rate. The effect of impressed-current on sensitivity of adiabatic shear of TC6 titanium alloy has been studied. It is shown that the impressed-current can reduce the sensitivity of adiabatic shear of TC6 titanium alloy under the condition of high strain-rate. Free electron in the samples will do direct move and take heat away from high localized area to decrease the effect of the heat. The result will help to delay formation of the adiabatic shear band. So, that is reducing the sensitivity of adiabatic shear of TC6 titanium alloy.

scholarly journals Changes in Mechanical Properties of Ultrahigh Strength Nanostructured Steel Resulting from Repeated High Strain Rate Deformation

2019 ◽  
Vol 10 (1) ◽  
pp. 99-120
Author(s):  
Jarosław MARCISZ ◽  
Bogdan GARBARZ ◽  
Jacek JANISZEWSKI
Keyword(s):  
Mechanical Properties ◽  
High Strain Rate ◽  
Strain Rate ◽  
Strain Hardening ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Isothermal Heat Treatment ◽  
Hopkinson Pressure Bar ◽  
Repeated Impact

The paper contains results of investigation of nanostructured bainitic steel subjected to repeated high-strain-rate deformations using split Hopkinson pressure bar method and uniaxial compression of cylindrical specimens in Gleeble simulator. Steel of chemical composition Fe-0.58%C-1.80%Si-1.95%Mn-1.3Cr-0.7Mo (weight %), after isothermal heat treatment at 210°C, is characterized by following mechanical properties determined at static tensile test: yield strength YS0.2 = 1.3 GPa; ultimate tensile strength UTS = 2.05 GPa; total elongation E = 12%, hardness 610 HV and Charpy-V impact toughness 24 J at +20℃ and 14 J at -40℃. Stress-strain curves obtained for pre-stressed material before the next dynamic compression and after repeated compressions were analysed. Microstructure of the deformed specimens in areas of the dynamic impact was investigated. The effects of the dynamic repeated impact on changes in characteristics of the investigated material, in that on strain hardening mechanism, were established. Critical strains of 5.3% at strain rate 910 s-1 and about 10% at strain rate 50 s-1 for the nanostructured bainite were determined. Exceeding the critical strain under uniaxial repeated high-strain-rate compression, resulted in decreasing of ability of the steel for further plastic deformation and strain hardening.

Effects of Temperature and Moisture on the High Strain Rate Compression Response of Graphite/Epoxy Composites

2003 ◽  
Vol 125 (4) ◽  
pp. 394-401 ◽  
Author(s):  
M. V. Hosur ◽  
S. M. Waliul Islam ◽  
U. K. Vaidya ◽  
P. K. Dutta ◽  
S. Jeelani
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
Experimental Investigations ◽  
Hopkinson Pressure Bar ◽  
Pressure Bar

Experimental investigations were carried out on unidirectional Graphite/Epoxy laminate samples under dynamic compression loading using a modified Split Hopkinson Pressure Bar. High strain rate testing was carried out at room and elevated temperatures. 30 layered graphite/epoxy unidirectional laminates made using DA 4518U unidirectional prepregs system were fabricated. Tests were carried out on samples at room, 51.7°C, 121.1°C, and 190.6°C temperatures. Additional high strain rate tests were conducted on samples that were subjected to moist/freeze conditioning for 42 days. Failure modes were studied through scanning electron microscopy. Results of the study indicated plasticizing of matrix which was reflected through increased ductility of the samples as well as reduced slope of the stress-strain curves with the increase in temperature. Similar effect was evident in the samples that were subjected to moist/freeze conditioning.

Dynamic compression and tensile responses of an epoxy matrix composites at high strain rate

2020 ◽  
pp. 095440622094322
Author(s):  
HX Hu ◽  
LM Meng ◽  
ZW Liu ◽  
XY Chen ◽  
HL Qin ◽  
...  
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Epoxy Resin ◽  
High Strain ◽  
Dynamic Compression ◽  
Resin Matrix ◽  
Matrix Composites ◽  
Stress Strain ◽  
Rich Phase ◽  
Epoxy Resin Matrix

To study the dynamic compression and tensile mechanical behaviors of a bicomponent epoxy resin matrix composites, which were filled with a semi-crystalline thermoplastic Polyether-ether ketone (PAEK-C) resin, at high strain rate, the dynamic compression and tensile experiments were carried out on a modified split Hopkinson pressure bar (SHPB) and high speed material apparatus, respectively. Stress-strain curves of the epoxy resin matrix composites were obtained and analyzed. Damage mechanism under high strain rate was characterized through the scanning electron microscope (SEM) observation. Results of the dynamic compression tests indicated that, although the effects of strain rate remarkably influenced the variations in stress, the behaviors of the epoxy resin matrix played a more significant role than strain rate in the determination of the high strain rate. It was reflected through increased ductility of the samples and reduced slope of the stress-strain curves. The dynamic impact tensile tests results show that, PAEK-C fillers exhibited dramatic toughening effect. The increase of the volume fraction of PAEK-C rich phase inevitably forces the crack to overcome more tearing deformation of PAEK-C rich phase. At the same time, the enhancement of plastic capacity may also induce a larger range of cooperative deformation at the crack tip.

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