scholarly journals Study of mechanical performance of polymer nanocomposites reinforced with exfoliated graphite of different mesh sizes using micro-indentation

2021 ◽  
pp. 002199832199321
Author(s):  
S Khammassi ◽  
M Tarfaoui ◽  
K Lafdi
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Exfoliated Graphite ◽  
Displacement Curve ◽  
Particle Sizes ◽  
Reinforced Polymers ◽  
Indentation Tests ◽  
Nano Additives ◽  
The Right ◽  
Micro Indentation

The first phase of this work aims to use the right additive nano-fillers choices, such as exfoliated Graphite (ExG), increasing the mechanical, electrical, and thermal performances. In this work, we are interested in quantifying the effect particles' size on a polymer matrix's performance. For this, three sets of exfoliated polymers filled with Graphite, characterized by three particle sizes, called meshes 50, 100, and 150, were investigated. In this analysis, exfoliated Graphite reinforced polymers were subjected to indentation tests to define local mechanical properties. The sample is an epoxy 862 matrix reinforced with exfoliated graphite additives. For each specific size, the additives are mixed in percentages of 0% in the act of control, 0.5%, 4%, 8%, and 16% by weight. Matching pure polymers, polymers reinforced by exfoliated Graphite have proven to have significant improvements in local elastic properties (such as modulus, hardness, stiffness, etc.). Results showed that the reinforced epoxy's local mechanical properties are affected by the size and the percentage of nano-additives. Through the inspection of the load-displacement curve, it can be concluded that the nano-additive has a significant influence on the plastic mechanical properties of the sample. Therefore, the size of nanoparticles has significantly improved in material properties.

Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests

Holzforschung ◽  
2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Stefanie Stanzl-Tschegg ◽  
Wilfried Beikircher ◽  
Dieter Loidl
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Thermal Treatment ◽  
Mechanical Performance ◽  
Growth Ring ◽  
Beech Wood ◽  
Thermal Modification ◽  
Wood Structure ◽  
Instrumented Indentation ◽  
Indentation Tests

Abstract Thermal modification is a well established method to improve the dimensional stability and the durability for outdoor use of wood. Unfortunately, these improvements are usually accompanied with a deterioration of mechanical performance (e.g., reduced strength or higher brittleness). In contrast, our investigations of the hardness properties in the longitudinal direction of beech wood revealed a significant improvement with thermal modification. Furthermore, we applied instrumented indentation tests on different hierarchical levels of wood structure (growth ring and cell wall level) to gain closer insights on the mechanisms of thermal treatment of wood on mechanical properties. This approach provides a variety of mechanical data (e.g., elastic parameters, hardness parameters, and viscoelastic properties) from one single experiment. Investigations on the influence of thermal treatment on the mechanical properties of beech revealed similar trends on the growth ring as well as the on the cell wall level of the wood structure.

scholarly journals Biomimetic Deposition of Hydroxyapatite Layer on Titanium Alloys

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1447
Author(s):  
Madalina Simona Baltatu ◽  
Andrei Victor Sandu ◽  
Marcin Nabialek ◽  
Petrica Vizureanu ◽  
Gabriela Ciobanu
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloys ◽  
Orthopedic Implants ◽  
X Ray Diffraction ◽  
Metallic Biomaterials ◽  
Viable Solution ◽  
Indentation Tests ◽  
Good Biocompatibility ◽  
Materials Used ◽  
Micro Indentation

Over the last decade, researchers have been concerned with improving metallic biomaterials with proper and suitable properties for the human body. Ti-based alloys are widely used in the medical field for their good mechanical properties, corrosion resistance and biocompatibility. The TiMoZrTa system (TMZT) evidenced adequate mechanical properties, was closer to the human bone, and had a good biocompatibility. In order to highlight the osseointegration of the implants, a layer of hydroxyapatite (HA) was deposited using a biomimetic method, which simulates the natural growth of the bone. The coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro indentation tests and contact angle. The data obtained show that the layer deposited on TiMoZrTa (TMZT) support is hydroxyapatite. Modifying the surface of titanium alloys represents a viable solution for increasing the osseointegration of materials used as implants. The studied coatings demonstrate a positive potential for use as dental and orthopedic implants.

New Design of Aluminium Based Composites through Combined Method of Powder Metallurgy and Thixoforming

2014 ◽  
Vol 939 ◽  
pp. 68-75 ◽  
Author(s):  
Lygia Maria Policarpio Ferreira ◽  
Maria Helena Robert ◽  
Emin Bayraktar ◽  
Diana Zaimova
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
High Energy ◽  
Raw Material ◽  
Combined Method ◽  
Indentation Tests ◽  
Metal Chips ◽  
Aeronautical Industry ◽  
Semi Solid ◽  
Micro Indentation

The present study deals with a new design of aluminium alloy based composites reinforced with SiC particles and Si/Al2O3 powders through combined methods of powder metallurgy and thixoforming. Moreover, recycled machining chips are used as raw material, specifically AA7075 chips generated in the aeronautical industry. The proposed method is based on forming at high temperatures a compacted mixture of metal chips and reinforcing particles, with the metal in thixotropic semi-solid condition. Composites containing different SiC weight fractions (10, 20 and 30%) were produced and had their microstructure analyzed. Mechanical properties were evaluated by means of micro-indentation tests. General results show the feasibility of producing composites by the proposed route. Products with good mechanical properties could be obtained. The process, even still not completely optimized as some improvement still must be achieved, can bring a new possibility for the production of a noble material from recycled wastes, particularly important in the high energy spending Al industries.

The Deformation Mechanism at Pop-In: Monocrystalline Silicon under Nanoindentation with a Berkovich Indenter

2008 ◽  
Vol 389-390 ◽  
pp. 453-458 ◽  
Author(s):  
Li Chang ◽  
Liang Chi Zhang
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Loading Rate ◽  
Monocrystalline Silicon ◽  
Displacement Curve ◽  
Berkovich Indenter ◽  
Rapid Loading ◽  
Slope Change ◽  
Indentation Tests ◽  
Load Displacement

This paper investigates the “pop-in” behavior of monocrystalline silicon under nanoindentation with a Berkovich indenter. The indentation tests were carried out under ultra-low loads, i.e. 100 μN and 300 μN, with different loading/unloading rates. It was found that with the experimentally determined area function of the indenter tip, the mechanical properties of silicon can be accurately calculated from the load-displacement data, that a pop-in event represents the onset of phase transition, and that a lower loading rate favours a sudden volume change but a rapid loading process tends to generate a gradual slope change of the load-displacement curve.

Mechanical Properties of Wear Tested LIGA Nickel

2004 ◽  
Vol 841 ◽  
Author(s):  
N. R. Moody ◽  
J. M. Jungk ◽  
M. S. Kennedy ◽  
S. V. Prasad ◽  
D. F. Bahr ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Work Hardening ◽  
Friction And Wear ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Frictional Contacts ◽  
Indentation Tests ◽  
Work Hardening Coefficient ◽  
Silicon Based ◽  
Hardening Coefficient

ABSTRACTStrength, friction, and wear are dominant factors in the performance and reliability of materials and devices fabricated using nickel based LIGA and silicon based MEMS technologies. However, the effects of frictional contacts and wear on the mechanical performance of microdevices are not well-defined. To address these effects on performance of LIGA nickel, we have begun a program employing nanoscratch and nanoindentation. Nanoscratch techniques were used to generate wear patterns using loads of 100, 200, 500, and 990 μN with each load applied for 1, 2, 5, and 10 passes. Nanoindentation was then used to measure properties in each wear pattern correcting for surface roughness. The results showed a systematic increase in hardness with applied load and number of nanoscratch passes. The results also showed that the work hardening coefficient determined from indentation tests within wear patterns follows the work hardening behavior established from tensile tests, supporting use of a nanomechanics-based approach for studying mechanical properties of wear tested material.

scholarly journals Analysis on the Mechanical Performance of the Joints of the Wheel-coupler type formwork Support

2021 ◽  
Vol 261 ◽  
pp. 02070
Author(s):  
Shilong Jia ◽  
Fang Zhou ◽  
Zhongliang Chen
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
Mechanical Performance ◽  
Ultimate Bearing Capacity ◽  
Displacement Curve ◽  
Ansys Software ◽  
Rotational Stiffness ◽  
Non Linear ◽  
Tension And Compression ◽  
Load Displacement

In order to study the mechanical properties of the joints, ANSYS software was used to simulate and analyse the failure form, ultimate bearing capacity, load-displacement curve and the rotational stiffness of the wheel-coupler joint node under force. Results: The wheel-coupler joint node has obvious non-linear characteristics when subjected to force; The bilateral symmetric tension and compression state could better reflect the failure form and deformation of the joint; The rotational stiffness of the wheel-coupler joint node under tension and bending was greater than that under bending and torsion, and was greater than that under tension, bending and torsion.

Characterization and Modeling of Large Displacement Micro-/Nano-Indentation of Polymeric Solids

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Y. C. Lu ◽  
D. M. Shinozaki
Keyword(s):  
Large Strain ◽  
Large Displacement ◽  
Plastic State ◽  
Large Strains ◽  
Displacement Curve ◽  
Plastic Properties ◽  
Indentation Tests ◽  
The Mean ◽  
Strain Hardening Behavior ◽  
Micro Indentation

Large displacement micro-indentation tests have been performed on various polymeric solids to measure the plastic properties. Cylindrical flat-ended indenters with diameter in the range of 10–90 μm are mostly used. The mechanism of large-strain indentation has been examined with optical microscopy and finite element simulations. Results show that under a flat-tipped indenter, the material can quickly reach a fully plastic state. The size (diameter) of the plastic zone is constant in large-strain regions and unaffected by the exact tip profile (flat, spherical, and conical). The indentation stress-displacement curve at large strains is linear as a result of the steady-state plastic flow, from which the mean indentation pressure, a measure of yield strength, can be readily extrapolated. The indentation stress-displacement response is independent of the indenter diameters but strongly dependent on the strain-hardening behavior of the material and the friction between a material and an indenter. Compared with other shaped indenters, the flat-ended indenter requires the least penetration depth in order to probe the plastic properties of a material or structure.

Effects of particle sizes, wood to cement ratio and chemical additives on the properties of sesendok (Endospermum Diadenum) cement-bonded particleboard

2010 ◽  
Vol 7 (2) ◽  
pp. 57
Author(s):  
Jamaludin Kasim ◽  
Shaikh Abdul Karim Yamani ◽  
Ahmad Firdaus Mat Hedzir ◽  
Ahmad Syafiq Badrul Hisham ◽  
Mohd Arif Fikri Mohamad Adnan
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Cement Content ◽  
Particle Sizes ◽  
Thickness Swelling ◽  
Chemical Additives ◽  
Board Density ◽  
Cement Ratio ◽  
Aluminium Silicate ◽  
Cement Board

An experimental investigation was performed to evaluate the properties of cement-bonded particleboard made from Sesendok wood. The target board density was set at a standard 1200 kg m". The effect offarticle size, wood to cement ratio and the addition ofsodium silicate and aluminium silicate on the wood cement board properties has been evaluated. A change ofparticle size from 1.0 mm to 2.0 mm has a significant effect on the mechanical properties, however the physical properties deteriorate. Increasing the wood to cement ratio from 1:2.25 to 1:3 decreases the modulus ofrupture (MOR) by 11% and the addition ofsodium silicate improves valuesfurther by about 28% compared to the addition ofaluminum silicate. The modulus ofelasticity (MOE) in general increases with increasing cement content, but is not significantly affected by the addition ofsodium silicate or aluminium silicate, although the addition of their mixture (sodium silicate andaluminium silicate) consistentlyyields greater MOE values. Water absorption and thickness swelling is significantly affected by the inclusion ofadditives and better values are attained using higher wood to cement ratios.

Weldability - Behavior of Welded Reinforcement

2019 ◽  
Vol 70 (10) ◽  
pp. 3469-3472
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Characteristics ◽  
Mechanical Performance ◽  
Current Work ◽  
Carbon Equivalent ◽  
Work Process ◽  
Ultimate Limit

Weldability involves two aspects: welding behavior of components and safety in operation. The two aspects will be reduced to the mechanical characteristics of the elements and to the chemical composition. In the case of steel reinforcing rebar’s, it is reduces to the percentage of Cech(carbon equivalent) and to the mechanical characteristics: the yielding limit, the ultimate limit, and the elongations which after that represent the ductility class in which the re-bars is framed. The paper will present some types of steel reinforcing rebar’s with its mechanical characteristics and the welding behavior of those elements. In the current work, process-related behavior of welded reinforcement, joint local and global mechanical properties, and their correlation with behavior of normal reinforcement and also the mechanical performance resulted in this type of joints. Keywords: welding behavior, ultimate limit, reinforcing rebar’s

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