Effects of Meso-Scale Structure and Interactions on Macro-Scale Mechanical Properties in Polymeric Materials

2004 ◽  
Vol 261-263 ◽  
pp. 747-752
Author(s):  
Akira Shinozaki ◽  
Masaki Omiya ◽  
Hisahiro Inoue ◽  
Kikuo Kishimoto
Keyword(s):  
Mechanical Properties ◽  
Network Models ◽  
Fem Analysis ◽  
Polymeric Materials ◽  
Scale Structure ◽  
Polymer Chains ◽  
Scale Interactions ◽  
Macro Scale ◽  
The Relationship ◽  
Meso Scale

The mechanical properties of polymers are strongly influenced by meso-scale structure such as entanglement, orientation, folded chain, etc. However, the relationship between the meso-scale structure and macro-scale mechanical properties of polymers has not been clarified. In this paper, network models of polymer chains are introduced to simulate the meso-scale interactions. From the FEM analysis of this model, the effects of interactions on macro-scale mechanical properties are investigated.

scholarly journals Simulation of Deformation Behavior of Polymeric Materials by Chain Network Model

2006 ◽  
Vol 306-308 ◽  
pp. 983-988 ◽  
Author(s):  
Akira Shinozaki ◽  
Kikuo Kishimoto ◽  
Hirotsugu Inoue
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Large Strain ◽  
Network Models ◽  
Polymeric Materials ◽  
Scale Structure ◽  
3D Network ◽  
The Relationship ◽  
Meso Scale

The mechanical properties of polymers are strongly influenced by meso-scale (10-9~10-3 m) structure such as entanglement, molecular weight distribution, orientation, etc. It is important to understand the relationship between the mechanical properties of polymeric material and meso-scale structure. Some studies related to the relationship have been made. However detail of the relationship is still unclear. Especially, the studies emphasize on entanglement and branch are few. This study aims to clear the role of entanglement and branch for mechanical properties by simulating the meso-scale structure using 3D network models. In the models, there are two structures considered. One of them has no branch, and, others have branch. Large strain deformation of network models is evolved via improved molecular dynamics analysis.

A Study of Deformation Behavior in Polymer

2005 ◽  
Vol 297-300 ◽  
pp. 2922-2928
Author(s):  
Akira Shinozaki ◽  
Kikuo Kishimoto ◽  
Hirotsugu Inoue
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Deformation Behavior ◽  
Large Strain ◽  
Chemical Change ◽  
Network Models ◽  
Scale Structure ◽  
Dynamics Analysis ◽  
Uv Degradation ◽  
Meso Scale

The mechanical properties of polymers are strongly influenced by meso-scale (10-9-10-3 m) structure such as entanglement, molecular weight distribution, orientation, etc. It is well known that sunlight induces the UV degradation of polymers. The mechanical properties of polymer are strongly influenced by UV irradiation because of chemical change of meso-scale structure. However the detail relationship between the mechanical properties and chemical change of meso-scale structure is not clear. In this study, it is aimed to clear this relationship by the simulation. Network models considered the meso-scale structure are constructed. Degradation is described to delete the chain elements in the network model. Large strain deformation of these network models is evolved via molecular dynamics analysis improved by us. It is possible to describe the degradation by this method.

scholarly journals bmotif: a package for motif analyses of bipartite networks

2018 ◽  
Author(s):  
Benno I. Simmons ◽  
Michelle J. M. Sweering ◽  
Maybritt Schillinger ◽  
Lynn V. Dicks ◽  
William J. Sutherland ◽  
...  
Keyword(s):  
Scale Structure ◽  
Individual Species ◽  
Mathematical Framework ◽  
List Type ◽  
Bipartite Networks ◽  
Diverse Range ◽  
Wide Range ◽  
Macro Scale ◽  
Plant Pollinator ◽  
Meso Scale

AbstractBipartite networks are widely-used to represent a diverse range of species interactions, such as pollination, herbivory, parasitism and seed dispersal. The structure of these networks is usually characterised by calculating one or more metrics that capture different aspects of network architecture. While these metrics capture useful properties of networks, they only consider structure at the scale of the whole network (the macro-scale) or individual species (the micro-scale). ‘Meso-scale’ structure between these scales is usually ignored, despite representing ecologically-important interactions. Network motifs are a framework for capturing this meso-scale structure and are gaining in popularity. However, there is no software available in R, the most popular programming language among ecologists, for conducting motif analyses in bipartite networks. Similarly, no mathematical formalisation of bipartite motifs has been developed.Here we introduce bmotif: a package for counting motifs, and species positions within motifs, in bipartite networks. Our code is primarily an R package, but we also provide MATLAB and Python code of the core functionality. The software is based on a mathematical framework where, for the first time, we derive formal expressions for motif frequencies and the frequencies with which species occur in different positions within motifs. This framework means that analyses with bmotif are fast, making motif methods compatible with the permutational approaches often used in network studies, such as null model analyses.We describe the package and demonstrate how it can be used to conduct ecological analyses, using two examples of plant-pollinator networks. We first use motifs to examine the assembly and disassembly of an Arctic plant-pollinator community, and then use them to compare the roles of native and introduced plant species in an unrestored site in Mauritius.bmotif will enable motif analyses of a wide range of bipartite ecological networks, allowing future research to characterise these complex networks without discarding important meso-scale structural detail.

scholarly journals Optimization of mechanical and dielectric properties of poly(urethane–urea)-based dielectric elastomers via the control of microstructure

RSC Advances ◽  
2017 ◽  
Vol 7 (88) ◽  
pp. 55610-55619 ◽  
Author(s):  
Dong Xiang ◽  
Miao Liu ◽  
Guanliang Chen ◽  
Teng Zhang ◽  
Li Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dielectric Properties ◽  
Scale Structure ◽  
Dielectric Elastomers ◽  
Length Scale ◽  
Acrylonitrile Copolymer ◽  
The Relationship

In this work, we fabricated hydroxyl-terminated butadiene–acrylonitrile copolymer-based poly(urethane–urea) dielectric elastomers, and investigated the relationship between multi-length scale structure and dielectric, mechanical properties.

Multi-Scale Investigation on Residual Strength of Jacket Platform With Fatigue Crack Damage

2015 ◽  
Author(s):  
Ren Hua Wang ◽  
Xiang Zou ◽  
Pei Lin Dou ◽  
Yuan Yuan Fang ◽  
Guang-en Luo
Keyword(s):  
Fatigue Crack ◽  
Residual Strength ◽  
Scale Structure ◽  
Scale Model ◽  
Wave Load ◽  
Jacket Platform ◽  
Multi Scale ◽  
Extreme Load ◽  
Macro Scale ◽  
Meso Scale

Fatigue crack damage caused by the wave load brings the structure of jacket platform in service potential failure risk when subjected to the extreme load. However, there is lack of efficient method to evaluate the influence of crack damage on the structural performance because of the huge scale difference between the meso-scale damage and the macro-scale structure. Based on the multi-scale finite element method (FEM), to improve the efficiency of structural analysis, the damaged region of the structure is modeled with fine FE mesh (shell element) to describe the fatigue crack, and the undamaged area is modeled with coarse FE mesh (beam element). Furthermore, the applicability and superiority of this multi-scale model was validated through comparing the results obtained from the beam, multi-scale and shell models. The influence of the time-varying crack damage on the residual strength of jacket platform is then revealed based on the multi-scale FE model. The results show that the proposed multi-scale method can accurately describe fatigue crack damage in the macro-scale structure, and be applied to investigate the influence of meso-scale structural damage under the extreme load condition.

Residual Mechanical Parameters of Masonry Exposed to Fire: A New Numerical Approach

2015 ◽  
Vol 1119 ◽  
pp. 700-705
Author(s):  
Salvatore Russo ◽  
Francesca Sciarretta
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fem Analysis ◽  
Numerical Approach ◽  
Masonry Walls ◽  
Mechanical Parameters ◽  
Compressive Failure ◽  
Fire Resistance Test ◽  
Numerical Tools ◽  
The Relationship

The paper is part of a research that aims at investigating the relationship between fire and post-fire (i.e. residual) mechanical behaviour of masonry walls, paying attention to the possible exploitation of numerical tools for simplified approaches. The goal is to establish relationships between exposure severity under ISO834 conditions and decay in mechanical properties after exposure; the parameter of wall thickness is especially investigated, by choosing four different values (i.e. 12, 25, 38 and 51 cm). This is performed by means of FEM analysis with DIANA 9.4.4 software, simulating a standard ISO 834 fire resistance test followed by a mechanical compressive failure test on each investigated type of wall. The FE analyses’ outcomes allow to draw exponential expressions of the decay in compressive strength as a function of the exposure severity.

scholarly journals Change of Mechanical Properties of Polyethylene Film Materials during Their Modification by Technological Applications and during Aging

2020 ◽  
Vol 21 (3) ◽  
pp. 510-518
Author(s):  
N. I. Domantsevich ◽  
B. P. Yatsushyn
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characteristics ◽  
Raw Materials ◽  
Electronic Devices ◽  
Polymeric Materials ◽  
Mechanical Tests ◽  
External Factors ◽  
Polyethylene Film ◽  
Materials Used ◽  
The Relationship

Mechanical tests and studies of the structure of modified polyethylene film materials used as packaging elements of electronic devices have been carried out. The modification provided for the introduction of fillers of various types and technological additives that would facilitate the processing of raw materials and ensure a long service life. The peculiarities of changes in mechanical characteristics depending on the number and type of applications, as well as the course of processes under the influence of external factors are established. The relationship between changes in the structure and mechanical properties of polymeric materials is shown.

Sunlight exposure: the effects on the performance of paragliding fabric

2018 ◽  
Vol 69 (05) ◽  
pp. 381-389
Author(s):  
MENGÜÇ GAMZE SÜPÜREN ◽  
TEMEL EMRAH ◽  
BOZDOĞAN FARUK
Keyword(s):  
Mechanical Properties ◽  
Aging Process ◽  
Air Permeability ◽  
Sunlight Exposure ◽  
Test Results ◽  
Coating Materials ◽  
Strength Tests ◽  
Before And After ◽  
The Relationship ◽  
Dark Blue

This study was designed to explore the relationship between sunlight exposure and the mechanical properties of paragliding fabrics which have different colors, densities, yarn counts, and coating materials. This study exposed 5 different colors of paragliding fabrics (red, turquoise, dark blue, orange, and white) to intense sunlight for 150 hours during the summer from 9:00 a.m. to 3:00 p.m. for 5 days a week for 5 weeks. Before and after the UV radiation aging process, the air permeability, tensile strength, tear strength, and bursting strength tests were performed. Test results were also evaluated using statistical methods. According to the results, the fading of the turquoise fabric was found to be the highest among the studied fabrics. It was determined that there is a significant decrease in the mechanical properties of the fabrics after sunlight exposure. After aging, the fabrics become considerably weaker in the case of mechanical properties due to the degradation in both the dyestuff and macromolecular structure of the fiber

Meso-Scale Experimental & Numerical Studies for Predicting Macro-scale Performance of Advanced Reactive Materials (ARMs)

2015 ◽  
Author(s):  
Naresh Thadhani ◽  
Arun Gokhale ◽  
Jason Quenneville ◽  
Jennifer Breidenich ◽  
Manny Gonzales ◽  
...  
Keyword(s):  
Reactive Materials ◽  
Numerical Studies ◽  
Macro Scale ◽  
Meso Scale

Possibilities of using biodegradable polymeric materials in the agricultural sector

2020 ◽  
Vol 67 (2) ◽  
pp. 115-120
Author(s):  
Raisa A. Alekhina ◽  
Victoriya E. Slavkina ◽  
Yuliya A. Lopatina
Keyword(s):  
Mechanical Properties ◽  
Biodegradable Polymers ◽  
Biodegradable Polymer ◽  
Agricultural Sector ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Limiting Factors ◽  
Research Purpose ◽  
Biodegradable Materials ◽  
Advantages And Disadvantages

The article presents options for recycling polymers. The use of biodegradable materials is promising. This is a special class of polymers that can decompose under aerobic or anaerobic conditions under the action of microorganisms or enzymes forming natural products such as carbon dioxide, nitrogen, water, biomass, and inorganic salts. (Research purpose) The research purpose is in reviewing biodegradable materials that can be used for the manufacture of products used in agriculture. (Materials and methods) The study are based on open information sources containing information about biodegradable materials. Research methods are collecting, studying and comparative analysis of information. (Results and discussion) The article presents the advantages and disadvantages of biodegradable materials, mechanical properties of the main groups of biodegradable polymers. The article provides a summary list of agricultural products that can be made from biodegradable polymer materials. It was found that products from the general group are widely used in agriculture. Authors have found that products from a special group can only be made from biodegradable polymers with a controlled decomposition period in the soil, their use contributes to increasing the productivity of crops. (Conclusions) It was found that biodegradable polymer materials, along with environmental safety, have mechanical properties that allow them producing products that do not carry significant loads during operation. We have shown that the creation of responsible products (machine parts) from biodegradable polymers requires an increase in their strength properties, which is achievable by creating composites based on them. It was found that the technological complexity of their manufacture and high cost are the limiting factors for the widespread use of biodegradable polymers at this stage.

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