scholarly journals Strain-rate-dependent mechanical properties of the equine hoof wall.

1996 ◽  
Vol 199 (5) ◽  
pp. 1133-1146 ◽  
Author(s):  
M A Kasapi ◽  
J M Gosline
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Strain Rate ◽  
Tensile Tests ◽  
Bending Test ◽  
Strain Rates ◽  
Dynamic Tests ◽  
Electron Microscopic ◽  
Initial Modulus ◽  
Equine Hoof

The mechanical properties of fully hydrated equine hoof wall were examined at various loading rates in compact tension (CT) fracture, tensile and three-point bending dynamic tests to determine possible effects of hoof wall viscoelasticity on fracture toughness and tensile parameters. Four cross-head rates were used in CT tests: 1.7 x 10(-5), 1.7 x 10 (-3), 1.7 x 10(-2) and 2.5ms-1; four strain rates were used in tensile tests: 1.6 x 10(-3), 3.2 x 10(-2), 0.33 and 70s(-1). Speeds for the highest test rates were achieved using a large, custom-built impact pendulum. Bending test frequencies ranged from 0.04 to 200 Hz. In CT tests, both the initial modulus Ei and the stress intensity factor K rose with increasing strain rate (from 0.38 to 0.76 GPa for Ei and from 0.71 to 1.4 MN m-3/2 for K), whereas the fracture toughness parameter J remained constant at 12kJm-2. All tensile parameters except ultimate strain were sensitive to strain rate. Ei, total energy to breakage and maximum stress rose with increasing strain rate from 0.28 to 0.85 GPa, from 5.4 to 9.7 MJm-3 and from 17 to 31 MPa, respectively. Data from low-amplitude dynamic tests agreed well with Ei trends from CT and tensile tests. Direction of crack growth differed through the thickness of the wall, the pattern of which resembled a trilaminar ply. Although scanning electron microscopic examination of fracture surfaces revealed a decreasing pseudo-ductile behaviour with increasing strain rate, and ultimate tensile parameters are positively affected, equine hoof wall viscoelasticity does not appear to compromise fracture toughness at high strain rates.

scholarly journals New Approach In The Properties Evaluation Of Ultrafine-Grained OFHC Copper

2015 ◽  
Vol 60 (2) ◽  
pp. 605-614 ◽  
Author(s):  
T. Kvačkaj ◽  
A. Kováčová ◽  
J. Bidulská ◽  
R. Bidulský ◽  
R. Kočičko
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Wear Behaviour ◽  
Ofhc Copper ◽  
Strain Rates ◽  
Ultrafine Grained ◽  
Reduction Of Area ◽  
Pin On Disk

AbstractIn this study, static, dynamic and tribological properties of ultrafine-grained (UFG) oxygen-free high thermal conductivity (OFHC) copper were investigated in detail. In order to evaluate the mechanical behaviour at different strain rates, OFHC copper was tested using two devices resulting in static and dynamic regimes. Moreover, the copper was subjected to two different processing methods, which made possible to study the influence of structure. The study of strain rate and microstructure was focused on progress in the mechanical properties after tensile tests. It was found that the strain rate is an important parameter affecting mechanical properties of copper. The ultimate tensile strength increased with the strain rate increasing and this effect was more visible at high strain rates$({\dot \varepsilon} \sim 10^2 \;{\rm{s}}^{ - 1} )$. However, the reduction of area had a different progress depending on microstructural features of materials (coarse-grained vs. ultrafine-grained structure) and introduced strain rate conditions during plastic deformation (static vs. dynamic regime). The wear behaviour of copper was investigated through pin-on-disk tests. The wear tracks examination showed that the delamination and the mild oxidational wears are the main wear mechanisms.

The Effect of Strain Rate on the Mechanical Properties of Single Crystal NiAl

1990 ◽  
Vol 213 ◽  
Author(s):  
D.F. Lahrman ◽  
R.D. Field ◽  
R. Darolia
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Single Crystal ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Deformation Mechanisms ◽  
Strain Rates ◽  
Test Results ◽  
Work Hardening Rate ◽  
Crystallographic Orientations

ABSTRACTIn this study, the strain rate sensitivity of single crystal NiAl has been investigated by performing tensile tests as a function of temperature and two strain rates. Three crystallographic orientations, [100], [110], and [111] were studied. The tensile test results investigated include yield strength, work hardening rate and plastic strain to failure. The data are discussed in terms of deformation mechanisms in NiAl.

Multiscale Material Modeling and Simulation of the Mechanical Behavior of Dual Phase Steels Under Different Strain Rates: Parametric Study and Optimization

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Tarek M. Belgasam ◽  
Hussein M. Zbib
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Volume Fraction ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Dual Phase ◽  
Strain Rates ◽  
Microstructure Parameters ◽  
Dp Steels

Recent studies on developing dual phase (DP) steels showed that the combination of strength/ductility could be significantly improved when changing the volume fraction and grain size of phases in the microstructure depending on microstructure properties. Consequently, DP steel manufacturers are interested in predicting microstructure properties as well as optimizing microstructure design at different strain rate conditions. In this work, a microstructure-based approach using a multiscale material and structure model was developed. The approach examined the mechanical behavior of DP steels using virtual tensile tests with a full micro-macro multiscale material model to identify specific mechanical properties. Microstructures with varied ferrite grain sizes, martensite volume fractions, and carbon content in DP steels were also studied. The influence of these microscopic parameters at different strain rates on the mechanical properties of DP steels was examined numerically using a full micro-macro multiscale finite element method. An elasto-viscoplastic constitutive model and a response surface methodology (RSM) were used to determine the optimum microstructure parameters for a required combination of strength/ductility at different strain rates. The results from the numerical simulations were compared with experimental results found in the literature. The developed methodology proved to be a powerful tool for studying the effect and interaction of key strain rate sensitivity and microstructure parameters on mechanical behavior and thus can be used to identify optimum microstructural conditions at different strain rates.

BRITTLENESS PROBLEM OF PUDDLED STEEL RESULTING FROM MICROSTRUCTURAL DEGRADATION PROCESSES IN TERMS OF STATIC, CYCLIC AND DYNAMIC TESTS

2011 ◽  
Vol 162 (4) ◽  
pp. 254-269
Author(s):  
Grzegorz LESIUK ◽  
Józef RABIEGA ◽  
Mieczysław SZATA
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Tests ◽  
Critical Value ◽  
J Integral ◽  
Dynamic Tests ◽  
Initial State ◽  
Operating Period ◽  
Degradation Processes ◽  
Static Tensile

In the paper the investigation results of puddled steel from nineteenth-century constructions are presented. The results of static tensile tests after more than 130-year operating period: fracture toughness, the critical value of the J integral and the fatigue crack growth, and dynamic tests – toughness results are presented in this article. The results show a significant effect of degradation processes. The abovementioned processes caused the brittleness of puddled steel. All the tests were performed for the material in two states, i.e. post-operated and normalised ones. In accordance with the guidelines developed in the framework of the degradation theory [4] and its material aspects [8], normalising is designed to reproduce the microstructure of steel in the initial state. The results presented allow us to draw the conclusions about trends related to the nature and future negative changes in mechanical properties.

Effect of Temperature and Strain Rate on Mechanical Properties of 63Sn/37Pb Solder Alloy

1999 ◽  
Vol 121 (3) ◽  
pp. 179-185 ◽  
Author(s):  
X. Q. Shi ◽  
W. Zhou ◽  
H. L. J. Pang ◽  
Z. P. Wang
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Strain Rate ◽  
Wide Temperature Range ◽  
Tensile Tests ◽  
Testing Temperature ◽  
Effect Of Temperature ◽  
Strain Rates ◽  
Wide Range ◽  
Quantitative Manner

In this study, tensile tests of 63Sn/37Pb solder were carried out at various strain rates from 10−5 s−1 to 10−1 s−1 over a wide temperature range from −40°C to 125°C to study the effect of strain rate and testing temperature on the mechanical properties in a systematic manner. Based on these experimental data, a set of empirical formulae was derived by a statistical method to describe the effect of temperature and strain rate in a quantitative manner and explain the variation in the mechanical properties published in other reports. It is concluded that the empirical formulae can be used to characterize the mechanical properties of 63Sn/37Pb over a wide range of temperatures and strain rates.

Quasi-Static and Dynamic Tensile Properties of Ti-6Al-4V Alloy

2013 ◽  
Vol 58 (4) ◽  
pp. 1261-1265 ◽  
Author(s):  
M. Wojtaszek ◽  
T. Sleboda ◽  
A. Czulak ◽  
G. Weber ◽  
W.A. Hufenbach
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Thermomechanical Processing ◽  
Tensile Tests ◽  
Surface Strain ◽  
Measuring System ◽  
Strain Rates ◽  
Ballistic Performance ◽  
Structural Parts

Abstract Ti-6Al-4V alloy is widely used, mainly in aircraft industry, due to its low density, excellent corrosion/oxidation resistance and attractive mechanical properties. This alloy has relatively low formability, so forming parts of complex geometries out of this alloy requires precisely controlled thermomechanical processing parameters. In industrial conditions Ti-6Al-4V alloy is usually processed by forging or extrusion. Ti-6Al-4V alloy is applied for structural parts of aircrafts, which are often exposed to variable loads and high or cyclically changing strain rates. Moreover, Ti-6Al-4V alloy is often used for structural parts providing good ballistic performance. That is why the knowledge of the mechanical behaviour of this alloy under dynamic conditions is important. This work is aimed at the analysis of Ti-6Al-4V alloy behaviour under quasi-static and dynamic deformation conditions. Both dynamic and quasi-static tensile tests were performed in this research. Moreover, ARAMIS system, a non-contact and material independent measuring system providing accurate 2D displacements, surface strain values and strain rates, was applied. The influence of tensile test strain rate on chosen mechanical properties of the investigated alloy was also discussed. The investigations showed a significant influence of processing strain rate on the mechanical behaviour of Ti-6Al-4V alloy.

scholarly journals A Review on Mechanical Properties of Natural Fibre Reinforced Polymer Composites under Various Strain Rates

2021 ◽  
Vol 5 (5) ◽  
pp. 130
Author(s):  
Tan Ke Khieng ◽  
Sujan Debnath ◽  
Ernest Ting Chaw Liang ◽  
Mahmood Anwar ◽  
Alokesh Pramanik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Polymer Composites ◽  
Stress Transfer ◽  
Natural Fibre ◽  
Transfer Efficiency ◽  
Strain Rates ◽  
Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Fibre Matrix

With the lightning speed of technological evolution, the demand for high performance yet sustainable natural fibres reinforced polymer composites (NFPCs) are rising. Especially a mechanically competent NFPCs under various loading conditions are growing day by day. However, the polymers mechanical properties are strain-rate dependent due to their viscoelastic nature. Especially for natural fibre reinforced polymer composites (NFPCs) which the involvement of filler has caused rather complex failure mechanisms under different strain rates. Moreover, some uneven micro-sized natural fibres such as bagasse, coir and wood were found often resulting in micro-cracks and voids formation in composites. This paper provides an overview of recent research on the mechanical properties of NFPCs under various loading conditions-different form (tensile, compression, bending) and different strain rates. The literature on characterisation techniques toward different strain rates, composite failure behaviours and current challenges are summarised which have led to the notion of future study trend. The strength of NFPCs is generally found grow proportionally with the strain rate up to a certain degree depending on the fibre-matrix stress-transfer efficiency. The failure modes such as embrittlement and fibre-matrix debonding were often encountered at higher strain rates. The natural filler properties, amount, sizes and polymer matrix types are found to be few key factors affecting the performances of composites under various strain rates whereby optimally adjust these factors could maximise the fibre-matrix stress-transfer efficiency and led to performance increases under various loading strain rates.

Mechanical Properties of Zirconia Toughened Alumina Composites with TZP Partially Nanostructured Sintered by Liquid Fase

2008 ◽  
Vol 591-593 ◽  
pp. 436-440
Author(s):  
João Marcos K. Assis ◽  
Francisco Piorino Neto ◽  
Francisco Cristóvão Lourenço de Melo ◽  
Maria do Carmo de Andrade Nono
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Weibull Modulus ◽  
Bending Test ◽  
Sintering Aid ◽  
Zirconia Composites ◽  
Alumina Composites ◽  
Grain Size And Shape ◽  
Zirconia Toughened Alumina ◽  
Zirconia Powders

A comparative study between alumina added niobia ceramics and two alumina zirconia composites from nanostructured TZP (7% and 14% weight) was made. On this composites the zirconia were yttria stabilized and the alumina were submicron structured. As sintering aid a mixture of magnesia, niobia and talc were used on all samples. The sintering was performed at 1450 oC during 60 minutes. The characteristic grain size and shape of an alumina and zirconia powders, aggregates and agglomerates were characterized. The sintering ceramics were evaluated through hardness, fracture toughness and 4 point bending test. Weibull statistic was applied on the flexural results. Although the fracture toughness result from ZTA were lower, and seems to be affected by the liquid fase, the hardness and Weibull modulus were higher than alumina niobia. The grains size and the homogeneity of its distributions on the microstructure of this ceramics was correlated to these higher values. The results from these alumina zirconia composites showed a potential to apply as a ballistic armor material.

scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cross Section ◽  
Negative Impact ◽  
Tensile Tests ◽  
Thermal Recovery ◽  
Bending Test ◽  
Small Scale ◽  
Spruce Wood ◽  
The Impact

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

scholarly journals Static Mechanical Properties of Expanded Polypropylene Crushable Foam

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 249
Author(s):  
Przemysław Rumianek ◽  
Tomasz Dobosz ◽  
Radosław Nowak ◽  
Piotr Dziewit ◽  
Andrzej Aromiński
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strain Rate ◽  
Energy Absorption ◽  
Experimental Tests ◽  
Absorption Capacity ◽  
Strain Rates ◽  
Foam Density ◽  
Energy Absorption Capacity ◽  
Closed Cell

Closed-cell expanded polypropylene (EPP) foam is commonly used in car bumpers for the purpose of absorbing energy impacts. Characterization of the foam’s mechanical properties at varying strain rates is essential for selecting the proper material used as a protective structure in dynamic loading application. The aim of the study was to investigate the influence of loading strain rate, material density, and microstructure on compressive strength and energy absorption capacity for closed-cell polymeric foams. We performed quasi-static compressive strength tests with strain rates in the range of 0.2 to 25 mm/s, using a hydraulically controlled material testing system (MTS) for different foam densities in the range 20 g/dm3 to 220 g/dm3. The above tests were carried out as numerical simulation using ABAQUS software. The verification of the properties was carried out on the basis of experimental tests and simulations performed using the finite element method. The method of modelling the structure of the tested sample has an impact on the stress values. Experimental tests were performed for various loads and at various initial temperatures of the tested sample. We found that increasing both the strain rate of loading and foam density raised the compressive strength and energy absorption capacity. Increasing the ambient and tested sample temperature caused a decrease in compressive strength and energy absorption capacity. For the same foam density, differences in foam microstructures were causing differences in strength and energy absorption capacity when testing at the same loading strain rate. To sum up, tuning the microstructure of foams could be used to acquire desired global materials properties. Precise material description extends the possibility of using EPP foams in various applications.

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