Mechanical properties of high-performance elastomeric nanocomposites: a sequential mesoscale simulation approach

RSC Advances ◽  
2014 ◽  
Vol 4 (108) ◽  
pp. 63586-63595 ◽  
Author(s):  
Shengwei Deng ◽  
Yongmin Huang ◽  
Shouhong Xu ◽  
Shaoliang Lin ◽  
Honglai Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Simulation Method ◽  
Simulation Approach ◽  
Mesoscale Simulation ◽  
Mechanical Responses

A sequential mesoscale simulation method was adopted to formulate elastomeric nanocomposites with desired macroscopic mechanical responses.

Improvement of warpage prediction through integrative simulation approach for thermoplastic material

2020 ◽  
pp. 089270572093074
Author(s):  
Mahesh Divekar ◽  
Vivek R Gaval ◽  
Andreas Wonisch
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Material Model ◽  
Simulation Method ◽  
Simulation Approach ◽  
Polybutylene Terephthalate ◽  
Temperature Dependent ◽  
Actual Measurement ◽  
Molded Parts ◽  
Moldflow Simulation

In the injection-molded parts, prediction of accurate warpage at initial level becomes mandatory to avoid iterative work of mold modifications. Simulation teams of many organizations are using existing commercial programs for process simulations. Material models in existing simulation technologies are having certain limitations and assumptions, which can regularly result in up to 50% variation of warpage results as compared to the actual physical warpage measurement. The commonly used Moldflow simulation model, for example, ignores temperature-dependent mechanical properties and the stress relaxation spectrum for viscoelastic materials. These assumptions affect the accuracy of the warpage prediction results significantly. To decrease these kinds of variations, BASF extended its Ultrasim® tool which is based on integrative simulation technology. Recently, a newly developed thermomechanical material model with temperature-dependent nonlinear mechanical properties and stress relaxation behavior was added in the Ultrasim. This model has been used in this work to consider the complete transient description of the warpage, which starts at packing phase of the part inside the mold, followed by actual cooling and ejection. In this article, unreinforced semicrystalline polybutylene terephthalate polymer material (Ultradur® B4520) is considered for warpage correlational study. The accuracy of the warpage prediction is compared between the integrative simulation approach, existing warpage simulation method, and the actual experimental inspection results. The result exhibits that the accuracy of the integrative simulation (Ultrasim)-based warpage simulation is relatively better than existing simulation technologies and closer to the actual measurement.

Experimental Investigation of Transverse Mechanical Properties of High-Performance Kevlar KM2 Single Fiber

2017 ◽  
Author(s):  
Hermise Raju ◽  
Assimina A. Pelegri
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Infinite Plate ◽  
Fiber Surface ◽  
Transversely Isotropic ◽  
Optical Microscope ◽  
Analytical Models ◽  
Flat Punch ◽  
Mechanical Responses ◽  
Transverse Fiber

Transverse nanoindentation modulus of high performance Kevlar KM2 single fibers are experimentally studied using a nanoindenter. Researchers have investigated the transverse compression behavior of these fibers using flat punch indentation heads, in which the curved circular transverse shape of the fiber is not included, and consecutively fit the data into the analytical models to calculate their mechanical properties. During this process, the force is normalized to a point on the transverse fiber surface and the analytical model assumes a flat semi-infinite plate for substrate. Other studies consider embedding the fibers on a substrate and indenting on the transverse surface. This method bounds the fibers resulting in inaccurate measurements of their mechanical responses. There has not been an appropriate study on the transverse material properties of the Kevlar fibers determined via nanoindentation without embedding them because it is challenging to rigidly secure the fibers. Here, we have developed a methodology to secure the Kevlar fiber on an SEM puck under pretension. The tension at the fiber is calculated and accounted for in the final determination of the mechanical properties. Fibers are glued at the ends and are not embedded. The employed Vantage nanoimpactor indents the fiber radially at three different loads, namely, 2, 3, and 5 mN and calculates the mechanical properties. A Berkovich indenter is used for indentation. The Kevlar fibers are assumed transversely isotropic and have 12μm diameter measured via the Vantage optical microscope. For Kevlar KM2 fiber the experimental transverse modulus using impact nanoindenter instrument is ∼3.46 GPa. The presented experiments aim to improve our understanding of the mechanical properties of these high performance fibers on the transverse direction.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

Mechanical properties and durability of high - performance concrete for bridge decks

PCI Journal ◽  
2008 ◽  
Vol 53 (4) ◽  
pp. 108-130
Author(s):  
Mohsen A. Issa ◽  
Atef A. Khalil ◽  
Shahidul Islam ◽  
Paul D. Krauss
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Bridge Decks

BERYLCO 25S

Alloy Digest ◽  
1952 ◽  
Vol 1 (3) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Precipitation Hardening ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Good Resistance ◽  
Subzero Temperatures ◽  
Endurance Strength ◽  
Wear And Corrosion ◽  
Resistance To Wear

Abstract Berylco 25S alloy is the high-performance beryllium-copper spring material of 2 percent nominal beryllium content. It responds to precipitation-hardening for maximum mechanical properties. It has high elastic and endurance strength, good electrical and thermal conductivity, excellent resistance to wear and corrosion, high corrosion-fatigue strength, good resistance to moderately elevated temperatures, and no embrittlement or loss of normal ductility at subzero temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-3. Producer or source: Beryllium Corporation.

EFFECT OF ZINC DITHIOCARBAMATES AND THIAZOLE-BASED ACCELERATORS ON THE VULCANIZATION OF NATURAL RUBBER

2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Reaction Mechanism ◽  
Natural Rubber ◽  
High Performance ◽  
Binary Systems ◽  
Synergistic Activity ◽  
Tetramethylthiuram Disulfide

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.

Stochastic simulation for determining the design flood of cascade reservoir systems

2012 ◽  
Vol 43 (1-2) ◽  
pp. 54-63 ◽  
Author(s):  
Baohong Lu ◽  
Huanghe Gu ◽  
Ziyin Xie ◽  
Jiufu Liu ◽  
Lejun Ma ◽  
...  
Keyword(s):  
Simulation Model ◽  
Stochastic Simulation ◽  
Southern China ◽  
Flow Simulation ◽  
Simulation Method ◽  
Simulation Approach ◽  
Design Flood ◽  
Design Values ◽  
Stochastic Simulation Model ◽  
The Impact

Stochastic simulation is widely applied for estimating the design flood of various hydrosystems. The design flood at a reservoir site should consider the impact of upstream reservoirs, along with any development of hydropower. This paper investigates and applies a stochastic simulation approach for determining the design flood of a complex cascade of reservoirs in the Longtan watershed, southern China. The magnitude of the design flood when the impact of the upstream reservoirs is considered is less than that without considering them. In particular, the stochastic simulation model takes into account both systematic and historical flood records. As the reliability of the frequency analysis increases with more representative samples, it is desirable to incorporate historical flood records, if available, into the stochastic simulation model. This study shows that the design values from the stochastic simulation method with historical flood records are higher than those without historical flood records. The paper demonstrates the advantages of adopting a stochastic flow simulation approach to address design-flood-related issues for a complex cascade reservoir system.

scholarly journals Enhancement of Chloroprene/Natural/Butadiene Rubber Nanocomposite Properties Using Organoclays and Their Combination with Carbon Black as Fillers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1085
Author(s):  
Patricia Castaño-Rivera ◽  
Isabel Calle-Holguín ◽  
Johanna Castaño ◽  
Gustavo Cabrera-Barjas ◽  
Karen Galvez-Garrido ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
High Performance ◽  
Rubber Matrix ◽  
Butadiene Rubber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rubber Blends ◽  
Ft Ir ◽  
Chloroprene Rubber

Organoclay nanoparticles (Cloisite® C10A, Cloisite® C15) and their combination with carbon black (N330) were studied as fillers in chloroprene/natural/butadiene rubber blends to prepare nanocomposites. The effect of filler type and load on the physical mechanical properties of nanocomposites was determined and correlated with its structure, compatibility and cure properties using Fourier Transformed Infrared (FT-IR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and rheometric analysis. Physical mechanical properties were improved by organoclays at 5–7 phr. Nanocomposites with organoclays exhibited a remarkable increase up to 46% in abrasion resistance. The improvement in properties was attributed to good organoclay dispersion in the rubber matrix and to the compatibility between them and the chloroprene rubber. Carbon black at a 40 phr load was not the optimal concentration to interact with organoclays. The present study confirmed that organoclays can be a reinforcing filler for high performance applications in rubber nanocomposites.

scholarly journals 3D Printing of High Viscosity Reinforced Silicone Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
New Technologies ◽  
Three Dimensional ◽  
High Viscosity ◽  
Layer By Layer ◽  
Silicone Elastomers ◽  
Uv Curable ◽  
Octet Truss ◽  
Tunable Mechanical Properties

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.

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