Effect of Multiaxial Tensile Deformation on the Mechanical Properties of Semiflexible Polymeric Samples

2019 ◽  
Vol 123 (43) ◽  
pp. 9238-9249
Author(s):  
Sunil Kumar ◽  
Sudip Kumar Pattanayek
Keyword(s):  
Mechanical Properties ◽  
Tensile Deformation ◽  
Polymeric Samples

Molecular Dynamics Simulation of Crack Initiation of Aluminum under Tensile Deformation

2011 ◽  
Vol 378-379 ◽  
pp. 7-10
Author(s):  
Gui Xue Bian ◽  
Yue Liang Chen ◽  
Jian Jun Hu ◽  
Li Xu
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Elastic Constants ◽  
Tensile Deformation ◽  
Crack Nucleation ◽  
Tensile Load ◽  
Dynamics Simulation ◽  
Metal Aluminum ◽  
Impurity Metal

Molecular dynamics simulation was used to simulate the tension process of purity and containing impurity metal aluminum. Elastic constants of purity and containing impurity metal aluminum were calculated, and the effects of impurity on the elastic constants were also studied. The results show that O-Al bond and Al-Al bond near oxygen atoms could be the sites of crack nucleation or growth under tensile load, the method can be extended to research mechanical properties of other metals and alloys structures.

scholarly journals Influence of Uncoupled Diblock Molecules on Mechanical Properties of Styerene/Butadiene/ Styrene Triblock Copolymers

2012 ◽  
Vol 12 ◽  
pp. 149-156 ◽  
Author(s):  
Rameshwar Adhikari
Keyword(s):  
Mechanical Properties ◽  
Block Copolymers ◽  
Tensile Deformation ◽  
Triblock Copolymers ◽  
Large Strain ◽  
Deformation Behaviour ◽  
Mechanical Analysis ◽  
Transmission Electron ◽  
Star Block Copolymers ◽  
Butadiene Styrene

The influence of the presence of uncoupled polystyrene-block-polybutadiene (SB) diblock chains to polystyrene-block-polybutadiene-block-polystyrene (SBS) triblock copolymers on the mechanical properties of the latter has been studied by means of tensile testing and dynamic mechanical analysis preparing several lamellae forming SBS/ SB blends through solution casting. The microphase-separated morphology of the samples was investigated by transmission electron microscopy. Both large strain deformation tensile deformation behaviour and viscoelastic properties of the SBS block copolymers were found to be affected appreciably by the presence of uncoupled SB diblock. The storage modulus of linear SBS was found to drop more sharply in the plateau region than for the radial SBS at the same SB content. At low SB content (up to 20 wt.-% for linear SBS and still higher for radial one), the overall tensile properties was not negatively influenced. On the whole, star block copolymers were found to be less sensitive towards the presence of diblock.DOI: http://dx.doi.org/10.3126/njst.v12i0.6493 Nepal Journal of Science and Technology 12 (2011) 149-156

Mechanical Properties and Strain Transfer Behavior of Molybdenum Ditelluride (MoTe2) Thin Films

2021 ◽  
pp. 1-31
Author(s):  
Shoieb Ahmed Chowdhury ◽  
Katherine Inzani ◽  
Tara Pena ◽  
Aditya Dey ◽  
Stephen M. Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Change ◽  
Density Functional ◽  
Mechanical Response ◽  
Interatomic Potential ◽  
Tensile Deformation ◽  
Random Search ◽  
Mechanical Strain ◽  
Uniaxial Tensile ◽  
Strain Transfer

Abstract Transition metal dichalcogenides (TMDs) offer superior properties over conventional materials in many areas such as in electronic devices. In recent years, TMDs have been shown to display a phase switching mechanism under the application of external mechanical strain, making them exciting candidates for phase change transistors. Molybdenum ditelluride (MoTe2) is one such material that has been engineered as a strain-based phase change transistor. In this work, we explore various aspects of the mechanical properties of this material by a suite of computational and experimental approaches. Firstly, we present parameterization of an interatomic potential for modeling monolayer as well as multilayered MoTe2 films. For generating the empirical potential parameter set, we fit results from Density Functional Theory calculations using a random search algorithm called particle swarm optimization. The potential closely predicts structural properties, elastic constants, and vibrational frequencies of MoTe2 indicating a reliable fit. Our simulated mechanical response matches earlier larger scale experimental nanoindentation results with excellent prediction of fracture points. Simulation of uniaxial tensile deformation by Molecular Dynamics shows the complete non-linear stress-strain response up to failure. Mechanical behavior, including failure properties, exhibits directional anisotropy due to the variation of bond alignments with crystal orientation. Furthermore, we show the deterioration of mechanical properties with increasing temperature. Finally, we present computational and experimental evidence of an extended c-axis strain transfer length in MoTe2 compared to TMDs with smaller chalcogen atoms.

Effect of Interphase Boundary Character on Mechanical Properties in NiAl(β) Bicrystals with Ni 3Al(γ') Precipitates along Grain Boundary

2002 ◽  
Vol 753 ◽  
Author(s):  
Toshiya Sakata ◽  
Hiroyuki Y. Yasuda ◽  
Yukichi Umakoshi
Keyword(s):  
Mechanical Properties ◽  
Interphase Boundary ◽  
Fracture Stress ◽  
Room Temperature ◽  
Tensile Deformation ◽  
Deviation Angle ◽  
Boundary Character ◽  
Temperature Fracture ◽  
Boundary Sliding

ABSTRACTRole of the crystallography of Ni 3Al(γ') precipitates along grain boundaries of NiAl(β) in the mechanical properties was systematically investigated using β bicrystals with controlled orientations. γ' phase preferentially precipitated along βgrain boundaries showing a film-like shape. The selected variant of γ'-film satisfied the Kurdjumov-Sachs (K-S) relation with a neighboring βcrystal but it deviated from the relation with another adjacent βcrystal. In the course of tensile deformation at room temperature, fracture occurred preferentially at incoherent (β/γ') interphase boundary deviating from the K-S relation and the fracture stress decreased with increasing deviation angle. In contrast, the interphase boundary sliding occurred preferentially at irrational (β/γ') interface at 1073K. The sliding displacement increased with increasing deviation angle. Thus, the mechanical properties of β bicrystals with γ'-film were found to depend strongly on the interphase boundary character.

scholarly journals Rheological Solidification Behavior and Mechanical Properties of AZ91-Sn Alloys

Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 641 ◽  
Author(s):  
Di Tie ◽  
Boyu Zhang ◽  
Lufei Yan ◽  
Renguo Guan ◽  
Zhaoshan Ji ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Deformation ◽  
Eutectic Reaction ◽  
Az91 Alloy ◽  
Solidification Behavior ◽  
Magnesium Matrix ◽  
Solid Solution Strengthening ◽  
The Matrix ◽  
Deformation Behaviors ◽  
Solution Strengthening

The solidification and tensile deformation behaviors of rheo-cast AZ91-Sn alloys were revealed to study the effects of Sn alloying on improvement of AZ91 alloy’s mechanical properties. Two kinds of Mg17Al12 phases precipitated from the supersaturated magnesium matrix during rheo-solidification were observed: coarse discontinuous precipitates (DP) at grain boundaries and small-sized continuous precipitates (CP) inside grains. With increasing Sn content, the amount of Mg17Al12 phases was increased whilst the amount of Al atoms in the matrix was decreased. Due to the higher melting point of Mg2Sn than Mg17Al12, Mg2Sn precipitated earlier from the melt, and therefore provided heterogeneous nuclei for Mg17Al12 during the eutectic reaction. Due to grain refinement and solid solution strengthening, AZ91-2.4Sn (mass%) gained 52% increase in tensile strength and 93% increase in elongation compared with pure AZ91 alloy. The higher-density twins and microcracks induced by Sn alloying relaxed stress concentration during plastic deformation, so the fracture mode was transformed from cleavage fracture of pure AZ91 alloy to ductile fracture of AZ91-Sn alloys.

scholarly journals Preparation of Asphalt Concretes by Gyratory Compactor: A Case of Study with Rheological and Mechanical Aspects

2020 ◽  
Vol 10 (23) ◽  
pp. 8567
Author(s):  
Paolino Caputo ◽  
Pietro Calandra ◽  
Rosolino Vaiana ◽  
Vincenzo Gallelli ◽  
Giovanni De Filpo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Activation Energy ◽  
Energy Savings ◽  
Tensile Deformation ◽  
Environmental Issues ◽  
Exponential Factor ◽  
Air Voids ◽  
Chemical Mechanisms ◽  
Physico Chemical ◽  
Indirect Tensile

For asphalt concrete preparation in laboratory mix-design operations, bitumens are usually mixed with micrometer-sized particles (filler), sand and centimeter-sized crushed stones in a gyratory press at a temperature of about 140–155 °C depending on the bitumen viscosity, until adequate homogenization and compaction take place (air voids optimum). This requires energy consumption. To minimize it, the process needs to be optimized and is usually made empirically. The aim of this manuscript is to gain a comprehension of the physico-chemical mechanisms involved in the process by exploring: (i) the rheological properties (viscosity, activation energy) of a neat and RTFOT-aged bitumen, in presence and in absence of a filler, (ii) the volumetric and resistance behavior under the compaction in a standard Gyratory Compactor (GC) of their blends with aggregates and (iii) the mechanical properties (Indirect Tensile Strength, compression and tensile deformation) of the final products. Correlations between activation energy and pre-exponential factor of the viscosity on a side, and between viscosity, workability and final mechanical properties on the other side allowed to provide a rational interpretation of the physico-chemical processes involved in the framework of the physics of complex fluids. The scientific clues will be of help in optimizing the workability in asphalt concretes productions with obvious repercussions in terms of energy savings, useful for economic and environmental issues.

Effect of Grain Refinement on Mechanical Properties in 25Cr-1N Austenitic Steel

2010 ◽  
Vol 638-642 ◽  
pp. 3549-3554 ◽  
Author(s):  
Toshihiro Tsuchiyama ◽  
T. Onomoto ◽  
K. Tsuboi ◽  
Setsuo Takaki
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Stress Concentration ◽  
Grain Refinement ◽  
Intergranular Fracture ◽  
Tensile Deformation ◽  
Austenitic Steels ◽  
High Yield ◽  
Structure Characteristic ◽  
Step Heat Treatment

The Fe-25Cr-1N alloy produced by solution nitriding possesses extremely high yield strength owing to the solid solution strengthening by nitrogen. However, it was found that the steel exhibited an insufficient elongation because of the brittle intergranular fracture caused during the uniform tensile deformation. This is due to the marked stress concentration at grain boundaries, which is derived from the grain coarsening caused during long time solution nitriding and the development of planar dislocation structure characteristic of high nitrogen austenitic steels. The most effective way to reduce the stress concentration at grain boundary during deformation should be grain refinement. In this study, grain refinement was attempted by the two-step heat treatment for the Fe-25Cr-1N(-Mn) alloy, and then the mechanical properties were investigated by means of tensile tests and fatigue tests. The two-step heat treatment resulted in the grain refinement of austenite to 20 microns in diameter. The intergranular fracture was greatly suppressed from 70% (as-solution-nitrided) to 10% (grain-refined) in area fraction by the grain refinement. In addition, elongation was markedly increased with local necking. The yield stress and tensile strength were also increased, and thus, the fatigue limit is also raised by more than 30%.

Influence of Heat-Treatment and Rolling Conditions on the Mechanical Warm Forming Properties of Twin-Roll Cast AZ31

2017 ◽  
Vol 746 ◽  
pp. 184-191 ◽  
Author(s):  
Franz Berge ◽  
Marie Moses ◽  
Rudolf Kawalla ◽  
Madlen Ullmann
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Hot Rolling ◽  
Tensile Deformation ◽  
Warm Forming ◽  
Efficient Production ◽  
Research Strategies ◽  
Component Design ◽  
Roll Casting ◽  
Twin Roll

Magnesium sheets are used for wide-ranging applications in the automotive sector. In contrast to conventional magnesium processing routes for strips, twin-roll casting (TRC) and hot rolling is a cost-efficient production process for magnesium strips and sheets. As part of previous research strategies, the optimization of the thermomechanical treatment of magnesium alloys has resulted in excellent mechanical properties for the component design. However, the previously determined results at room temperature cannot be correlated with the warm forming behaviour during the component production. This is due to different deformation mechanisms, which are active at various temperatures. For TRC material, there is a lack of knowledge about the influence of heat-treatment and rolling on the final mechanical properties at hot working temperatures. This article depicts the investigations done on the influence of heat-treatment and hot rolling conditions on the mechanical properties of AZ31 strips at tensile deformation temperatures of 20 °C and 300 °C.

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