scholarly journals Experimental Measurements of Mechanical Properties of PUR Foam Used for Testing Medical Devices and Instruments Depending on Temperature, Density and Strain Rate

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4560 ◽  
Author(s):  
Zdenek Horak ◽  
Karel Dvorak ◽  
Lucie Zarybnicka ◽  
Hana Vojackova ◽  
Jana Dvorakova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Mechanical Testing ◽  
Medical Devices ◽  
Optical Microscope ◽  
Surgical Instruments ◽  
Effect Of Temperature ◽  
Experimental Measurements ◽  
Compression Tests ◽  
Biomedical Material

Rigid polyurethane (PUR) foam is products used as a biomedical material for medical device testing. Thermal stability is a very important parameter for evaluating the feasibility of use for testing surgical instrument load during drilling. This work aimed to perform experimental measurements to determine the dependence of the mechanical properties of a certified PUR on temperature, strain rate and density. Experimental measurements were realised for three types of the PUR samples with different density 10, 25 and 40 pounds per cubic foot. The samples were characterised in terms of their mechanical properties evaluated from tensile and compression tests at temperatures of 25 °C, 90 °C and 155 °C. Furthermore, the structures of the samples were characterised using optical microscope, their thermal properties were characterised by thermogravimetric analysis, and their density and stiffness with the effect of temperature was monitored. The results show that it is optimal not only for mechanical testing but also for testing surgical instruments that generate heat during machining. On the basis of experimental measurements and evaluations of the obtained values, the tested materials are suitable for mechanical testing of medical devices. At the same time, this material is also suitable for testing surgical instruments that generate heat during machining.

Effect of Temperature on the Structure and Mechanical Properties of Mechanically Alloyed Al-Nio Composite

2014 ◽  
Vol 59 (1) ◽  
pp. 121-126
Author(s):  
M. Zygmunt-Kiper ◽  
L. Blaz ◽  
M. Sugamata
Keyword(s):  
Mechanical Properties ◽  
Aluminum Oxide ◽  
Aluminum Matrix ◽  
Hot Extrusion ◽  
Effect Of Temperature ◽  
Compression Tests ◽  
Mechanically Alloyed ◽  
Structure Morphology ◽  
High Purity Aluminum ◽  
Extrusion Method

Abstract Mechanical alloying of high-purity aluminum and 10 wt.% NiO powders combined with powder vacuum compression and following hot extrusion method was used to produce an Al-NiO composite. Mechanical properties of as-extruded materials as well as the samples annealed at 823 K /6 h, were tested by compression at 293 K - 770 K. High mechanical properties of the material were attributed to the highly refined structure of the samples. It was found that the structure morphology was practically not changed during hot-compression tests. Therefore, the effect of deformation temperature on the hardness of as-deformed samples was very limited. The annealing of samples at 823 K/6 h induced a chemical reaction between NiO-particles and surrounding aluminum matrix. As a result, the development of very fine aluminum oxide and Al3Ni grains was observed.

scholarly journals Effect of temperature on the mechanical properties of 3D-printed PLA tensile specimens

2018 ◽  
Vol 24 (8) ◽  
pp. 1337-1346 ◽  
Author(s):  
Marzio Grasso ◽  
Lyes Azzouz ◽  
Paula Ruiz-Hincapie ◽  
Mauro Zarrelli ◽  
Guogang Ren
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Test ◽  
Optical Microscope ◽  
Middle Part ◽  
Gauge Length ◽  
Effect Of Temperature ◽  
Content Type ◽  
Relevant Effect ◽  
3D Printed

Purpose Recent advancements of 3D printing technology have brought forward the interest for this technique in many engineering fields. This study aims to focus on mechanical properties of the polylactic acid (PLA) feeding material under different thermal conditions for a typical fusion deposition of 3D printer system. Design/methodology/approach Specimens were tested under static loading within the range 20ºC to 60ºC considering different infill orientations. The combined effect of temperature and filament orientation is investigated in terms of constitutive material parameters and final failure mechanisms. The difference between feeding system before and post-3D printing was also assessed by mechanical test on feeding filament to verify the thermal profile during the deposition phase. Findings The results in terms of Young’s modulus, ultimate tensile strength (UTS), strain at failure (εf) and stress at failure (σf) are presented and discussed to study the influence of process settings over the final deposited material. Fracture surfaces have been investigated using an optical microscope to link the phenomenological interpretation of the failure with the micro-mechanical behaviour. Experimental results show a strong correlation between stiffness and strength with the infill orientation and the temperature values. Moreover, a relevant effect is related to deformed geometry of the filament approaching glass transition region of the polymer according to the deposition orientation. Research limitations/implications The developed method can be applied to optimise the stiffness and strength of any 3D-printed composite according to the infill orientation. Practical implications To avoid the failure of specimens outside the gauge length, a previously proposed modification to the geometry was adopted. The geometry has a parabolic profile with a curvature of 1,000 mm tangent to the middle part of the specimen. Originality/value Several authors have reported the stiffness and strength of 3D-printed parts under static and ambient temperature for different build parameters. However, there is a lack of literature on the combination of the latter with the temperature effects on the mechanical properties which this paper covers.

scholarly journals High Strain Rate Deformation Behavior and Recrystallization of Alloy 718

2021 ◽  
Author(s):  
Marie Anna Moretti ◽  
Biswajit Dalai ◽  
Paul Åkerström ◽  
Corinne Arvieu ◽  
Dimitri Jacquin ◽  
...  
Keyword(s):  
Strain Rate ◽  
Deformation Behavior ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Optical Microscope ◽  
Electron Back Scatter Diffraction ◽  
Alloy 718 ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
Recrystallized Grain Size

AbstractTo study the deformation behavior and recrystallization of alloy 718 in annealed and aged state, compression tests were performed using Split-Hopkinson pressure bar (SHPB) at high strain rates (1000 to 3000 s−1), for temperatures between 20 $$^\circ $$ ∘ C and 1100 $$^\circ $$ ∘ C (293 K to 1373 K). Optical microscope (OM) and electron back-scatter diffraction (EBSD) technique were employed to characterize the microstructural evolution of the alloy. The stress–strain curves show that the flow stress level decreases with increasing temperature and decreasing strain rate. In addition, up to 1000 $$^\circ $$ ∘ C, the aged material presents higher strength and is more resistant to deformation than the annealed one, with a yield strength around 200 MPa higher. For both states, dynamic and meta-dynamic recrystallization occurred when the material is deformed at 1000 $$^\circ $$ ∘ C and 1100 $$^\circ $$ ∘ C, leading to a refinement of the microstructure. As necklace structures were identified, discontinuous recrystallization is considered to be the main recrystallization mechanism. The recrystallization kinetics is faster for higher temperatures, as the fraction of recrystallized grains is higher and the average recrystallized grain size is larger after deformation at 1100 $$^\circ $$ ∘ C than after deformation at 1000 $$^\circ $$ ∘ C.

Mechanical Properties of ZDTP Tribofilms Measured by Nanoindentation: Strain Rate and Temperature Effects

2008 ◽  
Author(s):  
S. Bec ◽  
K. Demmou ◽  
J.-L. Loubet
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Film Formation ◽  
Point Of View ◽  
Effect Of Temperature ◽  
Zinc Dialkyldithiophosphate ◽  
Wear Rates ◽  
Versus Strain ◽  
Antiwear Action

This study aims to contribute to better understand the antiwear action of zinc dialkyldithiophosphate (ZDTP) additives used in car engine lubrication. The antiwear action of ZDTP is associated to the formation of a protective tribofilm onto the rubbing surface. On a mechanical point of view, the efficiency of ZDTP tribofilms results from equilibrium between film formation and wear rates, associated with appropriate rheological properties. In this work, the mechanical properties of a ZDTP tribofilm have been measured by nanoindentation in different test conditions in order to investigate the effect of temperature and strain rate. A Nanoindenter XP® entirely set into a climatic chamber was used to perform the nanoindentation tests. For all tests, an increase of the elastic modulus was observed from a threshold contact pressure value. This effect is similar to the anvil effect observed on polymers: in confined geometry, the elastic modulus increases versus hydrostatic pressure. For the tribofilm, in the studied range, this effect is enhanced at high temperature and low strain rate. Furthermore, when the temperature increases, a change in the rheological behavior of the tribofilm is observed. Up to about 50°C, the tribofilm exhibits viscoplastic behavior — the hardness increases versus strain rate — and above 50°C, the hardness decreases versus strain rate (“shear thinning-like” behavior).

Influence of Al-10RE Modification on Microstructure and Mechanical Properties of ZL203 Aluminum Alloy

2011 ◽  
Vol 365 ◽  
pp. 98-103
Author(s):  
De Quan Shi ◽  
Gui Li Gao ◽  
Zhi Wei Gao ◽  
Yan Liu Wang ◽  
Xu Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Mechanical Testing ◽  
Testing Machine ◽  
Optical Microscope ◽  
Elongation Rate ◽  
Holding Time ◽  
Holding Temperature ◽  
Universal Mechanical Testing Machine

The influence of Al-10RE addition, holding time and holding temperature on the microstructures and mechanical properties of ZL203 aluminum alloy has been studied respectively through using the optical microscope and the universal mechanical testing machine. The experimental results lead to the following conclusions. When Al-10RE addition is 1.0%-1.5%, the holding time is 15 minutes and the holding temperature is 730°C-750°C, the microstructure of Zl203 is perfect. With the increase of Al-10RE addition, the mechanical properties including tensile strength, elongation rate and hardness gradually increase. When the Al-10RE addition is 1.0%-1.5%, the mechanical properties reaches maximum. When the Al-10RE addition is above 1.5%, the mechanical properties decrease with the increase of Al-10RE addition.

Research Progress of Strain-Rate Effect on Mechanical Properties of Concrete

2014 ◽  
Vol 638-640 ◽  
pp. 1391-1396
Author(s):  
Hong Yu Zhou ◽  
Yi Bo Chen ◽  
Ya Ran Zhang ◽  
Hai Qian Wang
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Concrete Strength ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Research Progress ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
Strain Rate Effects ◽  
Deformation Properties

Introducing research progress of rate-dependent tests by domestic and foreign scholars, strain-rate effect on dynamic mechanical properties of concrete are reviewed. Classified descriptions of research results on dynamic load tests of concrete at home and abroad are provided, including uniaxial compression tests, uniaxial tensile tests, and multi-axis tests; strain-rate effects on concrete strength and deformation properties in each test are respectively discussed; and strain-rate effect on concrete energy absorption capability are described.

Hot isostatic pressing synthesis and mechanical properties of Al/Al–Cu–Fe composite materials

2008 ◽  
Vol 23 (4) ◽  
pp. 904-910 ◽  
Author(s):  
T. El Kabir ◽  
A. Joulain ◽  
V. Gauthier ◽  
S. Dubois ◽  
J. Bonneville ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Hot Isostatic Pressing ◽  
Constant Strain Rate ◽  
Rate Sensitivity ◽  
Icosahedral Phase ◽  
Compression Tests ◽  
Isostatic Pressing ◽  
Temperature Regimes ◽  
Mechanism Control

Metal-matrix composites are produced from Al powder and 30 vol% of icosahedral Al–Cu–Fe quasi-crystalline particles using a hot isostatic pressing technique. It is demonstrated that the initial icosahedral phase is transformed into the ω-Al70Cu20Fe10 tetragonal phase during the hot isostatic pressing (HIP) process. The mechanical properties of the composite were evaluated over the temperature range 293 to 773 K by performing compression tests at constant strain rate. The temperature dependence of the yield stress gives evidence of two temperature regimes with a transition temperature at approximately 423 K. Strain-rate sensitivity measurements support the change in rate-controlling deformation mechanisms at this temperature. It is proposed that cross-slip and/or climb mechanism control plastic flow. Finally, it is suggested that the phase transformation of the particle contributes positively to the improvement of the mechanical properties.

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