scholarly journals THE MANAGEMENT OF CHARACTERISTICS OF THE NEW TWO-LAYER RUBBER MATRIX SEALS

2020 ◽  
Vol 5 ◽  
pp. 60-68
Author(s):  
Jamaladdin Nuraddin Aslanov ◽  
Sevinc Malik Abasova ◽  
Zenfira Seydi Huseynli
Keyword(s):  
Gate Valve ◽  
Complex Loading ◽  
Scientific Basis ◽  
Rubber Matrix ◽  
Test Program ◽  
Deformation Anisotropy ◽  
Small Constant ◽  
New Models ◽  
The Matrix ◽  
Linear Loading

Rubber seals for closing devices operating in cold climates degrade quickly in aggressive environments at very low temperatures. As a result, leaks and failures occur in the closure devices. Therefore, there is a great need to develop a new model of rubber seals and develop their scientific basis. The article is devoted to increasing the sealing effect of rubber seals of machines and equipment, including closures, by introducing the anisotropy of the rubber matrix into its structure with control of the characteristics of hard closures obtained from rubber. For this purpose, new models of the gate valve design were obtained and new models of two-layer panel seals based on a modified rubber elastomer matrix are applied to these structures. For this, a test program is carried out in the form of an analytical trajectory of large, medium and small constant curves in two closed forms based on characteristic deformations to study the anisotropy of matrix deformations. It is found that the eigenvector of the deformation anisotropy of the matrix is not in the load trajectory before it collapses, it arises with a delay. This delay slows down the rate of destruction. This property of deceleration of the main eigenvector of the deformation anisotropy of the matrix is subjected to a very complex loading of the initial fields, in the latter sections it is also observed in samples No. 2, No. 3, tested along the trajectory of linear loading. This delay slows down the destruction rate. Thus, the direction of the deceleration property of the main eigenvector can be considered quite common. This leads to an increase in its resistance to wear in a highly aggressive environment

scholarly journals The Influence of Filler Size and Crosslinking Degree of Polymers on Mullins Effect in Filled NR/BR Composites

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2284
Author(s):  
Miaomiao Qian ◽  
Bo Zou ◽  
Zhixiao Chen ◽  
Weimin Huang ◽  
Xiaofeng Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Strain Energy ◽  
Mathematical Expression ◽  
Rubber Matrix ◽  
Mullins Effect ◽  
Butadiene Rubber ◽  
Crosslinking Degree ◽  
Test Range ◽  
Two Factors ◽  
The Matrix

Two factors, the crosslinking degree of the matrix (ν) and the size of the filler (Sz), have significant impact on the Mullins effect of filled elastomers. Herein, the result. of the two factors on Mullins effect is systematically investigated by adjusting the crosslinking degree of the matrix via adding maleic anhydride into a rubber matrix and controlling the particle size of the filler via ball milling. The dissipation ratios (the ratio of energy dissipation to input strain energy) of different filled natural rubber/butadiene rubber (NR/BR) elastomer composites are evaluated as a function of the maximum strain in cyclic loading (εm). The dissipation ratios show a linear relationship with the increase of εm within the test range, and they depend on the composite composition (ν and Sz). With the increase of ν, the dissipation ratios decrease with similar slope, and this is compared with the dissipation ratios increase which more steeply with the increase in Sz. This is further confirmed through a simulation that composites with larger particle size show a higher strain energy density when the strain level increases from 25% to 35%. The characteristic dependence of the dissipation ratios on ν and Sz is expected to reflect the Mullins effect with mathematical expression to improve engineering performance or prevent failure of rubber products.

The Mechanism of Getting New Composite Polymer Materials with Improved Hardness Properties

2021 ◽  
Vol 887 ◽  
pp. 85-90
Author(s):  
L.S. Elbakyan ◽  
I.V. Zaporotskova ◽  
D.E. Vilkeeva
Keyword(s):  
Carbon Nanotubes ◽  
Polymer Material ◽  
Single Layer ◽  
Scientific Basis ◽  
Strength Properties ◽  
Polymer Materials ◽  
Mechanical Mixing ◽  
Material Component ◽  
Adsorption Interaction ◽  
The Matrix

The main aims and the objectives of the study focused on solving current problems of nanomaterial science of new materials – creating the scientific basis for competitive methods of obtaining and controlling new composite materials having improved strength properties based on carbon-containing polymer matrices with nanotubes stabilized in them. A technology for obtaining experimental samples of nanocompositional polymer material based on polymethylmethacrylate, polybutylmethacrylate, and methacrylic acid doped with carbon nanotubes has been developed, using ultrasonic action and mechanical mixing of the composite mixture to achieve the most uniform distribution of nanotubes in the matrix. To determine the possibility of implementing the mechanism of adsorption interaction of the studied polymer material with the surface of carbon nanotubes, DFT calculations of the interaction of the polymer material component and single-layer carbon nanotubes of various types have been done.

scholarly journals Differences in Wear and Material Integrity of NAO and Low-Steel Brake Pads under Severe Conditions

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5531
Author(s):  
Edouard A. T. Davin ◽  
Anne-Lise Cristol ◽  
Arnaud Beaurain ◽  
Philippe Dufrénoy ◽  
Neomy Zaquen
Keyword(s):  
Heat Treatment ◽  
Gray Cast Iron ◽  
Organic Matrix ◽  
Third Body ◽  
Test Program ◽  
Brake Pads ◽  
The Matrix ◽  
Disc Configuration ◽  
Crack Faces ◽  
Reduced Scale

In this study, through severe reduced-scale braking tests, we investigate the wear and integrity of organic matrix brake pads against gray cast iron (GCI) discs. Two prototype pad materials are designed with the aim of representing a typical non-metal NAO and a low-steel (LS) formulation. The worn surfaces are observed with SEM. The toughness of the pad materials is tested at the raw state and after a heat treatment. During braking, the LS-GCI disc configuration produces heavy wear. The friction parts both keep their macroscopic integrity and wear appears to be homogeneous. The LS pad is mostly covered by a layer of solid oxidized steel. The NAO-GCI disc configuration wears dramatically and cannot reach the end of the test program. The NAO pad suffers many deep cracks. Compacted third body plateaus are scarce and the corresponding disc surface appears to be very heterogeneous. The pad materials both show similar strength at the raw state and similar weakening after heat treatment. However, the NAO material is much more brittle than the LS material in both states, which seems to favor the growth of cracks. The observations of crack faces suggest that long steel fibers in the LS material palliate the brittleness of the matrix, even after heat damage.

An elastic harmonic inclusion near a rigid harmonic inclusion loaded by a couple

2019 ◽  
Vol 84 (3) ◽  
pp. 555-566
Author(s):  
Xu Wang ◽  
Liang Chen ◽  
Peter Schiavone
Keyword(s):  
Rigid Inclusion ◽  
Elastic Inclusion ◽  
Complex Loading ◽  
Solution Procedure ◽  
External Loading ◽  
Surrounding Matrix ◽  
The Matrix ◽  
Mapping Techniques ◽  
Loading Parameter ◽  
Harmonic Inclusion

AbstractWe use conformal mapping techniques to solve the inverse problem concerned with an elastic non-elliptical harmonic inclusion in the vicinity of a rigid non-elliptical harmonic inclusion loaded by a couple when the surrounding matrix is subjected to remote uniform stresses. Both a size-independent complex loading parameter and a size-dependent real loading parameter are introduced as part of the solution procedure. The stress field inside the elastic inclusion is uniform and hydrostatic; the interfacial normal and tangential stresses as well as the hoop stress on the matrix side are uniform along each one of the two inclusion–matrix interfaces. The tangential stress along the interface of the elastic inclusion (free of external loading) vanishes, whereas that along the interface of the rigid inclusion (loaded by the couple) does not. A novel method is proposed to determine the area of the rigid inclusion.

Frictional Sliding of Microcracks under Compression

2004 ◽  
Vol 261-263 ◽  
pp. 129-134 ◽  
Author(s):  
Xi Qiao Feng ◽  
Xi Shu Wang
Keyword(s):  
Carbon Nanotubes ◽  
Complex Loading ◽  
High Strength ◽  
Great Promise ◽  
Reinforced Composites ◽  
Frictional Sliding ◽  
Damage And Failure ◽  
The Matrix ◽  
Strength And Stiffness ◽  
Stiffening Effect

It is of interest to understand damage and failure mechanisms of microcracks and their evolution as a function of loading history, especially in the case of complex loading. Owing to their superior mechanical and physical properties, carbon nanotubes (CNTs) seem to hold a great promise as an ideal reinforcing material for composites of high-strength and low-density. HOWEVER, In most of the experimental results, only modest improvements in the strength and stiffness have been achieved by incorporating carbon nanotubes in polymers. There are many factors that influence the overall mechanical property of CNT-reinforced composites, e.g. the weak bonding between CNTs and matrix, the waviness and agglomeration of CNTs. In the present paper, we use the Mori-Tanaka method to evaluate the effect of these factors on the moduli of CNTs-CNT-reinforced composites. It is established that the waviness and agglomeration may significantly reduce the stiffening effect of CNTs, while the interface between the matrix and CNTs influence the moduli of CNTs-reinforced composites little.In this paper, the frictional sliding of microcracks under complex triaxial loading is analyzed, and the obtained results are incorporated into the constitutive relation of microcrack-weakened brittle materials.

Evaluation on Microstructure of Aluminum Alloys Dedicated to Plasma Etcher

2011 ◽  
Vol 689 ◽  
pp. 343-349
Author(s):  
Zhi Hui Zhang ◽  
Shu Feng Liu ◽  
Ze Ming Sun ◽  
Xiao Dong Yan
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Anodic Oxidation ◽  
Scientific Basis ◽  
Secondary Phases ◽  
6061 Aluminum Alloy ◽  
Close Relationship ◽  
The Matrix ◽  
Hole Defects

The relationship between microstructure and anodic oxidation film on 6061 aluminum alloy dedicated to plasma etcher were mainly studied by OM, SEM and TEM. The results show that the quality of anodic oxidation film has close relationship with the microstructure of materials, the distribution of element and the morphology of secondary phases. The microstructure of foreign 6061 aluminum alloy is uniform, and there are not obviously segregation and cavity. Two kinds of secondary phases disperse over the grain, one is rich-Fe phase, and the other is Mg2Si. Certainly there are also few secondary phases distributing along the grain boundary. The sizes of all secondary phases are almost below 5mm. The size of rich-Fe phases in homemade aluminum alloys are about from 2mm to 15mm, these big-size phases will bring pin-hole defects, which form some channels sending F+ etc. into the matrix of aluminum alloy, then not only the equipment will be destroyed at last, but also products will be polluted. The evaluation on microstructure of aluminum alloy will provide scientific basis for nationalization of plasma etcher.

A Physically Based Model for Bake-Hardening Steels and Dent Resistance

2007 ◽  
Vol 539-543 ◽  
pp. 4232-4237 ◽  
Author(s):  
Jean Louis Uriarte ◽  
A. Perlade ◽  
X. Lemoine ◽  
M. Soler ◽  
V. Ballarin ◽  
...  
Keyword(s):  
Physical Phenomenon ◽  
Complex Loading ◽  
Design Criterion ◽  
Bake Hardening ◽  
Physically Based Model ◽  
Strain Ageing ◽  
Physically Based ◽  
The Matrix ◽  
Automotive Parts ◽  
Dislocation Behaviour

Arcelor produces « Bake-Hardening » steels for automotive outer panels, which present the advantages of a remarkable drawability combined with a significant hardening after stamping and paint baking by the car maker. This hardening enables to increase the dent resistance of those automotive parts. In order to give easy design criterion and support the development for new “bake-hardening” steels, a physically-based model for Bake-Hardening steels has been developed. It is suitable to predict: -the physical phenomenon of strain ageing based on Cottrell atmospheres formation. A detailed description of the strain ageing kinetics is given based on a generalized form of the Harper model taking into account the diffusion of carbon atoms in the stress field of a dislocation, progressive carbon depletion in the matrix and saturation of the available dislocation sites. -the plastic instabilities propagation during tensile testing according to Piobert–Lüders phenomenon using the finite element method. A local mechanical behaviour is introduced whose shape schematically describes the local dislocation behaviour. The effect of the grain size on the velocity of the Lüders’ band front is especially enlightened. -the effect of ageing process on dent resistance. To do so, a physical extension of the former approach to more complex loading paths is proposed.

The Migration of Extender Oil in Natural and Synthetic Rubber. VI. The Use of Oil Type Molecules as Penetrants to Elucidate Elastomeric Molecular Structure

1972 ◽  
Vol 45 (1) ◽  
pp. 278-292 ◽  
Author(s):  
B. G. Corman ◽  
M. L. Deviney ◽  
L. E. Whittington
Keyword(s):  
Free Volume ◽  
Critical Size ◽  
Cross Sectional Area ◽  
Rubber Matrix ◽  
Sectional Area ◽  
Fractional Free Volume ◽  
Cross Sectional ◽  
Expansion Technique ◽  
The Matrix ◽  
Volume Measurements

Abstract Previous work in diffusion of whole extender oil and extender oil fractions in practical rubber compounds has shown the nature of the rubber matrix to be the major controlling factor. Therefore, a sensitive diffusivity approach, using radiotracer labeled hydrocarbon penetrants of sizes comparable to the size of a rotating segment, was used to study various aspects of the matrix structure on penetrant diffusion for polybutadiene, styrene—butadiene, and Butyl rubbers. These results were compared with fractional free volume measurements made by a thermal expansion technique. Neither fractional free volume nor diffusivity of phenyldodecane, benz-a-anthracene, or n-octadecane was affected by 5-fold variations of crosslink density or by variations in loading of 10 to 80 parts of carbon black (HAF-LS); nor were they affected by changes from FEF to SAF black at a 50 phr level. Glass transition temperature and fractional free volume are both affected by increasing percentages of benzene or phenyldodecane, While diffusivity rises with increasing dilution, states of equal free volume in different elastomers are not states of equal diffusivity; for example, at a fractional free volume of 0.10, corresponding to 20% benzene in both polybutadiene and Butyl at 70° C, the diffusivity of benzene in Butyl is lower by a factor of 15. Comparison of diffusivity of large penetrants with their cross-sectional area gives two basic curves, one for flexible penetrants and another for molecularly rigid species. These results are explained in terms of a distribution of free volumes, wherein only holes above a critical size are effective in diffusion. Swelling the system with aromatic diluent greatly increases the total fractional free volume, but only slightly the number of holes above this critical size. To understand the diffusivity of rigid molecules in elastomers, a probability factor must be applied in estimating their effective cross-sectional area.

scholarly journals Development of SBR-Nanoclay Composites with Epoxidized Natural Rubber as Compatibilizer

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
R. Rajasekar ◽  
Gert Heinrich ◽  
Amit Das ◽  
Chapal Kumar Das
Keyword(s):  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Damping Characteristics ◽  
Transmission Electron ◽  
Organically Modified ◽  
The Matrix ◽  
Styrene Butadiene

The significant factor that determines the improvement of properties in rubber by the incorporation of nanoclay is its distribution in the rubber matrix. The simple mixing of nonpolar rubber and organically modified nanoclay will not contribute for the good dispersion of nanofiller in the rubbery matrix. Hence a polar rubber like epoxidized natural rubber (ENR) can be used as a compatibilizer in order to obtain a better dispersion of the nanoclay in the matrix polymer. Epoxidized natural rubber and organically modified nanoclay composites (EC) were prepared by solution mixing. The nanoclay employed in this study is Cloisite 20A. The obtained nanocomposites were incorporated in styrene butadiene-rubber (SBR) compounds with sulphur as a curing agent. The morphology observed through X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) shows that the nanoclay is highly intercalated in ENR, and further incorporation of EC in SBR matrix leads to partial exfoliation of the nanoclay. Dynamic mechanical thermal analysis showed an increase in storage modulus and lesser damping characteristics for the compounds containing EC loading in SBR matrix. In addition, these compounds showed improvement in the mechanical properties.

scholarly journals Preparation and Assessment of Nanocomposites Based on Natural Rubber Latex Reinforced With Multiwall Carbon Nanotubes for Gamma Rays Shielding Applications

2021 ◽  
Author(s):  
A. Abdeldaym ◽  
M. A. Elhady
Keyword(s):  
Carbon Nanotubes ◽  
Natural Rubber ◽  
Natural Rubber Latex ◽  
Multiwall Carbon Nanotubes ◽  
Radiation Shielding ◽  
Nanocomposite Films ◽  
Rubber Matrix ◽  
The Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Shielding Properties

Abstract Reinforcement of the flexible shielding properties of natural rubber (NRL) was achieved through various content Multi-walled carbon nanotubes (MWCNTs) prepared from a simple solution using mixing method. Thereafter, a host of evaluative tests, using different techniques were carried to check the structural, morphological, mechanical and electrical conformity of the MWCNTs in the natural rubber matrix. More notably, the results from the x-ray diffraction (XRD), Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) revealed that the nanocomposites have been successfully prepared, making them fitting to impact significant improvement on the mechanical strength of the matrix. The evaluation of the formation of MWCNT networks in the matrix, which gives insight into the nanocomposites' electrical conductivity, also showed agreeable results as the linear attenuation coefficients (l) and half-value thickness (HVT) for NRL/MWCNTs nanocomposite films were investigated . Thus, from the foregoing series of results, it can be concluded that nanocomposite films offer promising radiation-shielding properties.

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