scholarly journals Strain hardening and shock mitigation response of polyurethane under high strain rates

AIP Advances ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 115306
Author(s):  
Amandeep Singh ◽  
V. D. Shivling ◽  
P. K. Khosla ◽  
Ashish Saini ◽  
Vijay Kumar ◽  
...  
Keyword(s):  
Strain Hardening ◽  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Shock Mitigation

scholarly journals Strain-Rate-Dependent Tensile Response of Ti–5Al–2.5Sn Alloy

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 659 ◽  
Author(s):  
Bin Zhang ◽  
Jin Wang ◽  
Yang Wang ◽  
Yu Wang ◽  
Ziran Li
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
Uniaxial Tension ◽  
Temperature Rise ◽  
High Strain ◽  
Adiabatic Temperature ◽  
High Rate ◽  
Strain Rates ◽  
High Strain Rates ◽  
Adiabatic Temperature Rise

This study is an experimental investigation on the tensile responses of Ti–5Al–2.5Sn alloy over a wide range of strain rates. Uniaxial tension tests within the rate range of 10−3–101 s−1 are performed using a hydraulic driven MTS810 machine and a moderate strain-rate testing system. The high-rate uniaxial tension and tension recovery tests are conducted using a split-Hopkinson tension bar to obtain the adiabatic and isothermal stress–strain responses of the alloy under dynamic loading conditions. The experimental results show that the value of the initial yield stress increases with the increasing strain rate, while the strain rate sensitivity is greater at high strain rates. The isothermal strain-hardening behavior changes little with the strain rate, and the adiabatic temperature rise is the main reason for the reduction of the strain-hardening rate during high strain-rate tension. The electron backscatter diffraction (EBSD) analysis of the post-deformed samples indicates that there are deformation twins under quasi-static and high-rate tensile loadings. Scanning electron microscope (SEM) micrographs of the fracture surfaces of the post-deformed samples show dimple-like features. The Zerilli–Armstrong model is modified to incorporate the thermal-softening effect of the adiabatic temperature rise at high strain rates and describe the tension responses of Ti–5Al–2.5Sn alloy over strain rates from quasi-static to 1050 s−1.

Dynamic Testing at High Strain Rates of AZ31 Magnesium Alloys on SHPB Equipment

2013 ◽  
Vol 303-306 ◽  
pp. 2648-2651
Author(s):  
Xu Qing Chang ◽  
Tie Hua Ma
Keyword(s):  
Strain Rate ◽  
Optical Microscopy ◽  
Strain Hardening ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Mg Alloy ◽  
Strain Rates ◽  
Hopkinson Pressure Bar ◽  
High Strain Rates ◽  
Az31 Mg Alloy

The mechanical behaviour of as-cast AZ31 Mg alloy has been investigated at strain rates up to 2.0×103s-1. Dynamic tests were carried out at room temperature using a Split Hopkinson Pressure Bar (SHPB) apparatus. Microstructural characteristic were analysed by Image MAT A1 optical microscopy. The results demonstrated that AZ31 Mg alloy exhibited obvious yield phenomena and strain hardening behaviour at high strain rates. The basically same curvature of stress-strain curves exhibited an similar strain hardening rate. The dynamic yield strength changes little and the peak stress increases with the strain rates. An examination by optical microscopy after high strain rate deformation reveals the occurrence of twinning and twin area percentage increases with the strain rate increasing.

Microstructural Evolution and Mechanical Behavior of Low Density Fe-Mn-Al-C Steels with High Stacking Fault Energy

2016 ◽  
Vol 879 ◽  
pp. 436-441
Author(s):  
H. Ding ◽  
Z.Q. Wu ◽  
D. Han ◽  
N. Zan ◽  
Wolfgang Bleck
Keyword(s):  
Mechanical Properties ◽  
Steady State ◽  
Strain Hardening ◽  
High Strain ◽  
Strong Increase ◽  
Low Density ◽  
Strain Rates ◽  
Planar Slip ◽  
High Strain Rates ◽  
Hardening Mechanisms

The microstructures and the mechanical properties of two Fe-26Mn-xAl-1C steels with 8 and 10 % Al have been investigated at different strain rates. The results show that Fe-26Mn-10Al-1C steel possesses higher strength and at the same time higher ductility than Fe-26Mn-8Al-1C steel at both low and high strain rates. The strengths of the steels increase and ductility declines slightly with increasing strain rate. These observations can be attributed to the different strain hardening mechanisms acting at different strain rates. Planar slip occurs and microbands form duringthe steady state stage, whereas deformation twinning occurs in the final stage ofdeformation. The higher strain hardening at high strain rates are due to the strong increase in the twinning propensity. The strain hardening at high strain rates also depends on the adiabatic heating, causing a competition between softening and strain hardening.

Material Behaviors of PBX Simulant with Various Strain Rates

2013 ◽  
Vol 535-536 ◽  
pp. 117-120 ◽  
Author(s):  
Chung Hee Park ◽  
Seh Wan Jeong ◽  
Hoon Huh ◽  
Jung Su Park
Keyword(s):  
Strain Hardening ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Materials Testing ◽  
Strain Rates ◽  
High Strain Rates ◽  
Material Behaviors ◽  
Compressive Tests

This paper is concerned with the material behaviors of PBX(Polymer Bonded eXplosive) simulant at various strain rates ranging from 0.0001/sec to 3150/sec. Material behaviors of PBX at the high strain rates are important in the prediction of deformation modes of PBX in a warhead which undergoes severe impact loading. Inert PBX stimulant which has analogous material behaviors with PBX was utilized for material tests due to safety issues. Uniaxial compressive tests at quasi-static and intermediate strain rates were conducted with cylindrical specimen using a dynamic materials testing machine, INSTRON 8801. Uniaxial compressive tests at high strain rates ranging from 1200/sec to 3150/sec were conducted using a split Hopkinson pressure bar. Deformation behaviors were investigated using captured images obtained from a high-speed camera. The strain hardening behaviors of PBX simulant were formulated by proposed strain rate-dependent strain hardening model.

High Strain Rate Compression Testing of Hot-Pressed TRIP/TWIP-Matrix-Composites

2017 ◽  
Vol 742 ◽  
pp. 113-120 ◽  
Author(s):  
Ralf Eckner ◽  
Lutz Krüger
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Deformation Mechanisms ◽  
Strain Rates ◽  
Strengthening Effect ◽  
Matrix Composites ◽  
High Strain Rates ◽  
The Matrix

Metal matrix composites with ceramic reinforcements such as particles or fibers have come into focus during the past decades due to rising requirements on engineering materials. In this work, composite materials out of high-alloy CrMnNi-steel matrices with varying Ni-contents (3 wt.% and 9 wt.%) and 10 vol.% Mg-PSZ were processed by hot-pressing. The variation in Ni-content resulted in a change in stacking fault energy (SFE) which significantly influenced the deformation mechanisms. The mechanical behavior of the developed composites was investigated in a wide strain rate range between 0.0004 s-1 and 2300 s-1 under compressive loading. This was done by a servohydraulic testing system, a drop weight tower, and a Split-Hopkinson Pressure Bar for the high strain rates. To study the influence on the deformation mechanisms such as martensitic transformations and/or twinning, interrupted tests were also carried out at 25 % compressive strain. Subsequent microstructural examinations were done by a magnetic balance to measure the quantity of α’-martensite as well as by scanning electron microscopy (SEM). The results show an increase of strength and strain hardening with decreasing SFE of the matrix due to increased α’-martensite formation. The addition of the Mg-PSZ particles resulted in further strengthening over almost the entire deformation range for all investigated composites. At high strain rates quasi-adiabatic heating suppressed the martensite transformation and reduced the strain hardening capacity of the matrix. Nonetheless the particle reinforcement retains its strengthening effect.

scholarly journals Behaviour of Strain-Hardening Cement-Based Composites Under High Strain Rates

2011 ◽  
Vol 9 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Viktor Mechtcherine ◽  
Flávio de Andrade Silva ◽  
Marko Butler ◽  
Deju Zhu ◽  
Barzin Mobasher ◽  
...  
Keyword(s):  
Strain Hardening ◽  
High Strain ◽  
Strain Rates ◽  
High Strain Rates

Abnormal strain hardening in nanostructured titanium at high strain rates and large strains

2006 ◽  
Vol 42 (5) ◽  
pp. 1751-1756 ◽  
Author(s):  
Y. M. Wang ◽  
J. Y. Huang ◽  
T. Jiao ◽  
Y. T. Zhu ◽  
A. V. Hamza
Keyword(s):  
Strain Hardening ◽  
High Strain ◽  
Large Strains ◽  
Strain Rates ◽  
High Strain Rates ◽  
Nanostructured Titanium

Dynamic Compression Behavior and Numerical Modeling of Ti-6246 Alloy at Different Temperatures

2012 ◽  
Vol 527 ◽  
pp. 159-164 ◽  
Author(s):  
Dmitri Gomon ◽  
Mikko Hokka ◽  
Veli Tapani Kuokkala
Keyword(s):  
Numerical Modeling ◽  
Strain Rate ◽  
Strain Hardening ◽  
High Strain ◽  
Material Behavior ◽  
Materials Testing ◽  
Strain Rates ◽  
High Strain Rates ◽  
Stress Strain ◽  
Strain Hardening Rate

The current research concentrates on the characterization of the mechanical behavior of Ti-6Al-2Sn-4Zr-6Mo alloy. The material was studied in compression using the Split Hopkinson Pressure Bar (SHPB) equipment at high strain rates and conventional servohydraulic materials testing devices at low strain rates. The tests were performed at temperatures ranging from room temperature up to 600 °C. According to the results of the compression tests, the strain hardening rate of the studied material decreases strongly with increasing strain rate. The observed strong decrease in the strain hardening rate with increasing strain rate is a consequence of the extremely strong adiabatic heating of the material due to its high strength and low thermal conductivity. In this study, the Johnson-Cook material model parameters were obtained from isothermal stress-strain curves that were calculated from the experimental (adiabatic) stress-strain data. In this paper, the results of the mechanical testing at high strain rates and the numerical modeling of the material behavior are presented and discussed in details.

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