scholarly journals Effect of the Strain Rate and Fiber Direction on the Dynamic Mechanical Properties of Beech Wood

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 881 ◽  
Author(s):  
Shumeng Pang ◽  
Yingjing Liang ◽  
Weijun Tao ◽  
Yijie Liu ◽  
Shi Huan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Beech Wood ◽  
Rate Sensitivity ◽  
Dynamic Mechanical Properties ◽  
Fiber Direction ◽  
Compression Tests ◽  
Static Compression ◽  
Dynamic Mechanical

As a macroscopically orthotropic material, beech wood has different mechanical properties along the fiber direction and the direction perpendicular to the fiber direction, presenting a complicated strain rate sensitivity under impact or blast loadings. To understand the effect of the strain rate on the mechanical properties of beech wood, dynamic compression tests were conducted for the strain rate range of 800 s−1–2000 s−1, and quasi-static compression tests for obtaining the static mechanical properties of beech wood were also performed for comparison. The fiber direction effect on the mechanical properties was also analyzed, considering two loading directions: one perpendicular to the beech fiber direction and the other parallel to the beech fiber direction. The results show that beech wood for both loading directions has a significant strain rate sensitivity, and the mechanical properties of beech wood along the fiber direction are superior to those along the direction perpendicular to the fiber direction. An analysis of the macrostructures and microstructures of beech specimens is also presented to illustrate the failure mechanisms. The beech wood, as a natural protective material, has special dynamic mechanical properties in the aspect of transverse isotropy. This research provides a theoretical basis for application in protective structures.

scholarly journals Dynamic Mechanical Compression Impulse of Lithium-Ion Pouch Cells

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2105 ◽  
Author(s):  
Alon Ratner ◽  
Richard Beaumont ◽  
Iain Masters
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Lithium Ion ◽  
Rate Sensitivity ◽  
Dynamic Mechanical Properties ◽  
Impact Testing ◽  
Significant Feature ◽  
Dynamic Mechanical ◽  
The Impact

Strain rate sensitivity has been widely recognized as a significant feature of the dynamic mechanical properties of lithium-ion cells, which are important for their accurate representation in automotive crash simulations. This research sought to improve the precision with which dynamic mechanical properties can be determined from drop tower impact testing through the use of a diaphragm to minimize transient shock loads and to constrain off-axis motion of the indenter, specialized impact absorbers to reduce noise, and observation of displacement with a high speed camera. Inert pouch cells showed strain rate sensitivity in an increased stiffness during impact tests that was consistent with the poromechanical interaction of the porous structure of the jellyroll with the liquid electrolyte. The impact behaviour of the inert pouch cells was similar to that of an Expanded Polypropylene foam (EPP), with the exception that the inert pouch cells did not show hysteretic recovery under the weight of the indenter. This suggests that the dynamic mechanical behaviour of the inert pouch cells is analogous to a highly damped foam.

Measurement on Strain Rate Sensitivity and Dynamic Mechanical Properties of Various Polymeric Materials

2011 ◽  
Vol 471-472 ◽  
pp. 385-390 ◽  
Author(s):  
Mohd Firdaus Omar ◽  
Md Akil Hazizan ◽  
Zainal Arifin Ahmad
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Polymeric Materials ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Wide Range

Strain rate sensitivity and dynamic mechanical properties of polymeric materials are affected to a certain extent especially by the rate of loading. However, there is limited number of works reported on that particular issue. Therefore, the paper presents on static and dynamic mechanical properties of various polymeric materials across strain rate from 10-2 to 10-3 s-1. The specimen were tested using universal testing machine (UTM) for static loading and a conventional split Hopkinson pressure bar (SHPB) apparatus for dynamic loading. From the results, the compression modulus and compressive strength of all tested specimen increased significantly with increasing strain rates. In addition, positive increment in terms of strain rate sensitivity was recorded for all tested polymers over a wide range of strain rate investigated. Meanwhile, the thermal activation volume has decreased as increasing strain rate. Of the three polymers, polypropylene shows the highest strain rate sensitivity at static region. On the other hand, at dynamic region, polycarbonate shows the highest strain rate sensitivity than that of polypropylene and polyethylene.

Effect of Particle Sizes on Rate Sensitivity and Dynamic Mechanical Properties of Polypropylene/Silica (PP/Sio2) Nanocomposites

2011 ◽  
Vol 364 ◽  
pp. 181-185 ◽  
Author(s):  
Firdaus Omar Mohd ◽  
Md Akil Hazizan ◽  
Zainal Arifin Ahmad
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Strain Rate ◽  
Testing Machine ◽  
Rate Sensitivity ◽  
Dynamic Mechanical Properties ◽  
Particle Sizes ◽  
Rate Condition ◽  
Dynamic Mechanical ◽  
Silica Nanocomposites

Filler-related characteristic such as particle size, shape and geometry are essential factors that need to be considered during the evaluation of the material’s performance especially in the area of particle filled composites. However, there is limited number of works are reported on this particular issue under high strain rate condition. Based on this concern, the paper presents an experimental results on the effect of particle sizes towards rate sensitivity and dynamic compressive properties of polypropylene/silica nanocomposites across strain rate from 10-2to 10-3s-1. The composite specimens were tested using universal testing machine for static loading and a compression split Hopkinson pressure bar apparatus for dynamic loading. Results show that, the stiffness and strength properties of polypropylene/silica nanocomposites were affected by the size of silica particles. However, the magnitudes of changed are somehow different between micro and nanosizes. On the other hand, particle size also plays a major contribution towards sensitivity of the polypropylene/silica nanocomposites where the smaller the reinforcement sizes, the less sensitive would be the composites. Overall, it is convenience to say that the particle size gives significant contribution towards rate sensitivity and dynamic mechanical properties of polypropylene/silica nanocomposites.

scholarly journals Influence of Size Effect on Dynamic Mechanical Properties of OFHC Copper at Micro/Mesoscopic Scale

2021 ◽  
Author(s):  
Chuanzhi Jing ◽  
Jilai Wang ◽  
Chengpeng Zhang ◽  
Yan Sun ◽  
Zhenyu Shi
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Strain Rate ◽  
Size Effects ◽  
Dynamic Mechanical Properties ◽  
Experimental Results ◽  
Ofhc Copper ◽  
Static Compression ◽  
Dynamic Mechanical ◽  
Macro Scale

Abstract The dynamic mechanical properties of metallic materials have been extensively investigated at the macro-scale in terms of deformation mechanisms, strain rate strengthening, and fracture mechanisms. However, the dynamic mechanical properties affected by size effects at micro/meso-scales have rarely been investigated. To explore the size effects on the dynamic mechanical properties at micro/meso-scales, the experiments of quasi-static compression and SHPB were carried out using oxygen-free, high-conductivity (OFHC) copper with different geometrical and grain sizes. The experimental results show that the quasi-static and dynamic mechanical properties of OFHC copper are affected by size effects at micro/meso-scales. In particular, OFHC copper exhibits strain rate strengthening effects at the micro/meso-scales, and the presence of micro-cracks was observed in the SHPB experimental specimens. The J-C constitutive model based on the surface layer model is proposed and the analysis of the average relative error of the modified model and the original constitutive model is performed. Finite element analysis was carried out based on the modified J-C model and the original model, and the results show that the modified J-C model was in good agreement with the experimental results.

The Temperature Dependence of the Mechanical Properties of Gamma TiAl

1994 ◽  
Vol 364 ◽  
Author(s):  
B. Viguier ◽  
J. Bonneville ◽  
K. J. Hemker ◽  
J. L. Martin
Keyword(s):  
Mechanical Properties ◽  
Flow Stress ◽  
Strain Rate ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Dislocation Motion ◽  
Compression Tests ◽  
Wide Range

AbstractMechanical properties of a polycrystalline single phased γ Ti47Al51Mn2 alloy were studied by compression tests in a wide range of temperature (100 K - 1300 K). We report, in this paper, the temperature dependence of both the flow stress and its strain rate sensitivity. These dependencies show the existence of three temperature domains corresponding to different dislocation motion mechanisms. The temperature dependence of the flow stress strain rate sensitivity is compared with values measured in single crystals1.

Experimental Study on Dynamic Mechanical Properties of HPP Hybrid Fibers Reinforced Lightweight Aggregate Concrete

2014 ◽  
Vol 919-921 ◽  
pp. 1983-1989 ◽  
Author(s):  
Dan Wang ◽  
Zhi Kun Guo ◽  
Fei Shao ◽  
Wan Xiang Chen
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Lightweight Aggregate ◽  
Dynamic Mechanical Properties ◽  
Lightweight Aggregate Concrete ◽  
Compression Tests ◽  
Hybrid Fibers ◽  
Impact Compression ◽  
Aggregate Concrete ◽  
Dynamic Mechanical

The impact compression tests on HPP hybrid fibers reinforced lightweight aggregate concrete were performed with 100mm SHPB equipment. The dynamic mechanical properties and variation of HPP hybrid fibers reinforced lightweight aggregate concrete under different strain rates and loading methods were systematically studied. HPP hybrid fibers reinforced lightweight aggregate concrete is of the property of strain rate effects under impact loads as ordinary concrete. The dynamic strength and peak strain of it increased with the increase of strain rate. During multiple-impact compression tests, the specimens were able to bear multiple impacts before damage after cracks were produced. It is clear that HPP hybrid fibers reinforced lightweight aggregate concrete is an outstanding material for protective engineering to resist repetitive impacts.

Local Investigations of the Mechanical Properties of Ultrafine Grained Metals by Nanoindentations

2006 ◽  
Vol 503-504 ◽  
pp. 31-36 ◽  
Author(s):  
Johannes Mueller ◽  
Karsten Durst ◽  
Dorothea Amberger ◽  
Matthias Göken
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
Rate Sensitivity ◽  
Strain Rates ◽  
Fcc Metals ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Indentation Strain

The mechanical properties of ultrafine-grained metals processed by equal channel angular pressing is investigated by nanoindentations in comparison with measurements on nanocrystalline nickel with a grain size between 20 and 400 nm produced by pulsed electrodeposition. Besides hardness and Young’s modulus measurements, the nanoindentation method allows also controlled experiments on the strain rate sensitivity, which are discussed in detail in this paper. Nanoindentation measurements can be performed at indentation strain rates between 10-3 s-1 and 0.1 s-1. Nanocrystalline and ultrafine-grained fcc metals as Al and Ni show a significant strain rate sensitivity at room temperature in comparison with conventional grain sized materials. In ultrafine-grained bcc Fe the strain rate sensitivity does not change significantly after severe plastic deformation. Inelastic effects are found during repeated unloading-loading experiments in nanoindentations.

Effect of Graphene Nanoplatelets Content on Dynamic Mechanical Property of GNPs/Ti Composites

2018 ◽  
Vol 910 ◽  
pp. 123-129 ◽  
Author(s):  
X.N. Mu ◽  
H.N. Cai ◽  
Hong Mei Zhang ◽  
Q.B. Fan ◽  
Y. Wu
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Stress ◽  
Dynamic Compression ◽  
Dynamic Mechanical Properties ◽  
Graphene Nanoplatelets ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Dynamic Mechanical ◽  
Adiabatic Shearing

In this study, the titanium matrix composites (TiMCs) were fabricated by adding graphene nanoplatelets (GNPs). The dynamic compression test was carried out to study the effect of strain-rate and the GNPs content on dynamic mechanical properties of GNPs/Ti. Results show that the GNPs content (0wt%~0.8wt%) correspond to specific microstructure which affect the dynamic mechanical properties of the composites. Under high strain-rate (3500s-1), the 0.4wt%GNPs/Ti has the highest dynamic stress (~1860MPa) and strain (~30%). The adiabatic shearing band (ASB) microstructure of GNPs/Ti with various GNPs content has been observed under 3500s-1 strain-rate and the ASB microstructure evolution of 0.4wt%GNPs/Ti under different strain rate was investigated in particular.

scholarly journals Strain-Rate-Dependent Deformation Behavior and Mechanical Properties of a Multi-Phase Medium-Manganese Steel

Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 344 ◽  
Author(s):  
Simon Sevsek ◽  
Christian Haase ◽  
Wolfgang Bleck
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Deformation Behavior ◽  
Rate Sensitivity ◽  
Manganese Steel ◽  
Strain Rates ◽  
Rate Dependent ◽  
Medium Manganese Steel ◽  
Multi Phase

The strain-rate-dependent deformation behavior of an intercritically annealed X6MnAl12-3 medium-manganese steel was analyzed with respect to the mechanical properties, activation of deformation-induced martensitic phase transformation, and strain localization behavior. Intercritical annealing at 675 °C for 2 h led to an ultrafine-grained multi-phase microstructure with 45% of mostly equiaxed, recrystallized austenite and 55% ferrite or recovered, lamellar martensite. In-situ digital image correlation methods during tensile tests revealed strain localization behavior during the discontinuous elastic-plastic transition, which was due to the localization of strain in the softer austenite in the early stages of plastic deformation. The dependence of the macroscopic mechanical properties on the strain rate is due to the strain-rate sensitivity of the microscopic deformation behavior. On the one hand, the deformation-induced phase transformation of austenite to martensite showed a clear strain-rate dependency and was partially suppressed at very low and very high strain rates. On the other hand, the strain-rate-dependent relative strength of ferrite and martensite compared to austenite influenced the strain partitioning during plastic deformation, and subsequently, the work-hardening rate. As a result, the tested X6MnAl12-3 medium-manganese steel showed a negative strain-rate sensitivity at very low to medium strain rates and a positive strain-rate sensitivity at medium to high strain rates.

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