scholarly journals Strain-rate sensitivity of electrically modified carbon/epoxy composites under dynamic compressive loading

2020 ◽  
Vol 28 ◽  
pp. 1664-1672
Author(s):  
Sahand P. Shamchi ◽  
Anurag Singh ◽  
Carmen Sguazzo ◽  
Zhongjie Zhao ◽  
Xiaosu Yi ◽  
...  
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Compressive Loading ◽  
Rate Sensitivity ◽  
Epoxy Composites ◽  
Dynamic Compressive Loading

Effect of Consolidation and Sintering Parameters on the Mechanical Responses of Nanocrystalline Al-Fe Alloy Processed by Mechanical Alloying

2015 ◽  
Vol 719-720 ◽  
pp. 87-90
Author(s):  
Muneer Baig ◽  
Hany Rizk Ammar ◽  
Asiful Hossain Seikh ◽  
Mohammad Asif Alam ◽  
Jabair Ali Mohammed
Keyword(s):  
Mechanical Alloying ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Compressive Loading ◽  
Rate Sensitivity ◽  
Testing Temperature ◽  
Fine Grained ◽  
Mechanical Responses ◽  
Wide Range ◽  
High Frequency Induction

In this investigation, bulk ultra-fine grained and nanocrystalline Al-2 wt.% Fe alloy was produced by mechanical alloying (MA). The powder was mechanically milled in an attritor for 3 hours and yielded an average crystal size of ~63 nm. The consolidation and sintering was performed using a high frequency induction sintering (HFIS) machine at a constant pressure of 50 MPa. The prepared bulk samples were subjected to uniaxial compressive loading over wide range of strain rates for large deformation. To evaluate the effect of sintering conditions and testing temperature on the strain rate sensitivity, strain rate jump experiments were performed at high temperature. The strain rate sensitivity of the processed alloy increased with an increase in temperature. The density of the bulk samples were found to be between 95 to 97%. The average Vickers micro hardness was found to be 132 Hv0.1.

scholarly journals Strain Rate Sensitivity of Epoxy Composites Reinforced with Varied Sizes of Bagasse Particles

2020 ◽  
Vol 4 (3) ◽  
pp. 110
Author(s):  
Sujan Debnath ◽  
Tan Ke Khieng ◽  
Mahmood Anwar ◽  
Animesh Kumar Basak ◽  
Alokesh Pramanik
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Interfacial Strength ◽  
Rate Sensitivity ◽  
Natural Fibre ◽  
Filler Loading ◽  
Epoxy Composites ◽  
Fibre Reinforced Polymer ◽  
Filler Particles

Viscoelastic materials, such as natural fibre-reinforced polymer composites, are strain rate sensitive. In the present investigation, the low strain rate sensitivity (0.00028 s−1, 0.00085 s−1 and 0.0017 s−1) of different sized bagasse particle-reinforced (212 µm and 300 µm) epoxy composites was examined using the Weibull analysis method. The filler loading content was optimized at 2 wt.% to achieve better mechanical properties. Based on the experimental results, it was observed that composites with 212 µm filler particles had higher characteristic strengths, more consistent failure strengths and higher energy absorption properties with higher loading speeds, compared to that of 300 µm filler particles. Based on the mathematical models for particle–matrix interactions, improvements in mechanical properties are attributed to proper filler dispersion and a better fibre–matrix interfacial strength.

scholarly journals Rate sensitivity and tension–compression asymmetry in AZ31B magnesium alloy sheet

2014 ◽  
Vol 372 (2015) ◽  
pp. 20130216 ◽  
Author(s):  
Srihari Kurukuri ◽  
Michael J. Worswick ◽  
Dariush Ghaffari Tari ◽  
Raja K. Mishra ◽  
Jon T. Carter
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Compressive Loading ◽  
Rate Sensitivity ◽  
Strain Response ◽  
Basal Texture ◽  
Stress Strain ◽  
Strong Basal Texture ◽  
Tension Compression Asymmetry

The constitutive response of a commercial magnesium alloy rolled sheet (AZ31B-O) is studied based on room temperature tensile and compressive tests at strain rates ranging from 10 −3 to 10 3  s −1 . Because of its strong basal texture, this alloy exhibits a significant tension–compression asymmetry (strength differential) that is manifest further in terms of rather different strain rate sensitivity under tensile versus compressive loading. Under tensile loading, this alloy exhibits conventional positive strain rate sensitivity. Under compressive loading, the flow stress is initially rate insensitive until twinning is exhausted after which slip processes are activated, and conventional rate sensitivity is recovered. The material exhibits rather mild in-plane anisotropy in terms of strength, but strong transverse anisotropy ( r -value), and a high degree of variation in the measured r -values along the different sheet orientations which is indicative of a higher degree of anisotropy than that observed based solely upon the variation in stresses. This rather complex behaviour is attributed to the strong basal texture, and the different deformation mechanisms being activated as the orientation and sign of applied loading are varied. A new constitutive equation is proposed to model the measured compressive behaviour that captures the rate sensitivity of the sigmoidal stress–strain response. The measured tensile stress–strain response is fit to the Zerilli–Armstrong hcp material model.

scholarly journals Negative Strain Rate Sensitivity Induced by Structure Heterogeneity in Zr64.13Cu15.75Ni10.12Al10 Bulk Metallic Glass

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 339
Author(s):  
Xiang Wang ◽  
Zhi Qiang Ren ◽  
Wei Xiong ◽  
Si Nan Liu ◽  
Ying Liu ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Strain Rate Sensitivity ◽  
Critical Role ◽  
Rate Sensitivity ◽  
Confined Compression ◽  
Negative Strain Rate Sensitivity ◽  
Cast Specimen ◽  
Structure Heterogeneity

The negative strain rate sensitivity (SRS) of metallic glasses is frequently observed. However, the physical essence involved is still not well understood. In the present work, small-angle X-ray scattering (SAXS) and high-resolution transmission electron microscopy (HRTEM) reveal the strong structure heterogeneity at nanometer and tens of nanometer scales, respectively, in bulk metallic glass (BMG) Zr64.13Cu15.75Ni10.12Al10 subjected to fully confined compression processing. A transition of SRS of stress, from 0.012 in the as-cast specimen to −0.005 in compression processed specimen, was observed through nanoindentation. A qualitative formulation clarifies the critical role of internal stress induced by structural heterogeneity in this transition. It reveals the physical origin of this negative SRS frequently reported in structurally heterogeneous BMG alloys and its composites.

Strain rate sensitivity of a 1.5 GPa nanotwinned steel

2021 ◽  
Author(s):  
R.D. Liu ◽  
Y.Z. Li ◽  
L. Lin ◽  
C.P. Huang ◽  
Z.H. Cao ◽  
...  
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity

scholarly journals The Strain Rate Sensitivity and Creep Behavior for the Tripler Plane of Potassium Dihydrogen Phosphate Crystal by Nanoindentation

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 369
Author(s):  
Jianhui Mao ◽  
Wenjun Liu ◽  
Dongfang Li ◽  
Chenkai Zhang ◽  
Yi Ma
Keyword(s):  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Creep Deformation ◽  
Potassium Dihydrogen Phosphate ◽  
Rate Sensitivity ◽  
Dislocation Nucleation ◽  
Machining Process ◽  
Dihydrogen Phosphate ◽  
Potassium Dihydrogen ◽  
Kdp Crystals

As an excellent multifunctional single crystal, potassium dihydrogen phosphate (KDP) is a well-known, difficult-to-process material for its soft-brittle and deliquescent nature. The surface mechanical properties are critical to the machining process; however, the characteristics of deformation behavior for KDP crystals have not been well studied. In this work, the strain rate effect on hardness was investigated on the mechanically polished tripler plane of a KDP crystal relying on nanoindentation technology. By increasing the strain rate from 0.001 to 0.1 s−1, hardness increased from 1.67 to 2.07 GPa. Hence, the strain rate sensitivity was determined as 0.053, and the activation volume of dislocation nucleation was 169 Å3. Based on the constant load-holding method, creep deformation was studied at various holding depths at room temperature. Under the spherical tip, creep deformation could be greatly enhanced with increasing holding depth, which was mainly due to the enlarged holding strain. Under the self-similar Berkovich indenter, creep strain could be reduced at a deeper location. Such an indentation size effect on creep deformation was firstly reported for KDP crystals. The strain rate sensitivity of the steady-state creep flow was estimated, and the creep mechanism was qualitatively discussed.

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