scholarly journals Optically transparent, high-toughness elastomer using a polyrotaxane cross-linker as a molecular pulley

2018 ◽  
Vol 4 (10) ◽  
pp. eaat7629 ◽  
Author(s):  
Hiroaki Gotoh ◽  
Chang Liu ◽  
Abu Bin Imran ◽  
Mitsuo Hara ◽  
Takahiro Seki ◽  
...  
Keyword(s):  
External Force ◽  
Matrix Material ◽  
Three Dimensional ◽  
Cross Linking ◽  
High Toughness ◽  
Dimensional Network ◽  
Cyclic Molecules ◽  
Optically Transparent ◽  
The Matrix ◽  
Special Challenge

An elastomer is a three-dimensional network with a cross-linked polymer chain that undergoes large deformation with a small external force and returns to its original state when the external force is removed. Because of this hyperelasticity, elastomers are regarded as one of the best candidates for the matrix material of soft robots. However, the comprehensive performance required of matrix materials is a special challenge because improvement of some matrix properties often causes the deterioration of others. For example, an improvement in toughness can be realized by adding a large amount of filler to an elastomer, but to the impairment of optical transparency. Therefore, to produce an elastomer exhibiting optimum properties suitable for the desired purpose, very elaborate, complicated materials are often devised. Here, we have succeeded in creating an optically transparent, easily fabricated elastomer with good extensibility and high toughness by using a polyrotaxane (PR) composed of cyclic molecules and a linear polymer as a cross-linking agent. In general, elastomers having conventional cross-linked structures are susceptible to breakage as a result of loss of extensibility at high cross-linking density. We found that the toughness of the transparent elastomer prepared using the PR cross-linking agent is enhanced along with its Young’s modulus as cross-linking density is increased.

Multiscale Modeling of Dynamic Characteristics of Carbon Nanotube Reinforced Nanocomposites

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650083 ◽  
Author(s):  
Sachin O. Gajbhiye ◽  
S. P. Singh
Keyword(s):  
Carbon Nanotube ◽  
Dynamic Characteristics ◽  
Matrix Material ◽  
Three Dimensional ◽  
Vacancy Defect ◽  
Nanocomposite Material ◽  
Phase Lag ◽  
Rate Dependent ◽  
Carbon Carbon Bond ◽  
The Matrix

A unique atomic structure of carbon nanotube unveils outstanding properties. This makes it potentially highly valued reinforcing material to strengthen composite materials. The methodology is established in this research paper to investigate the static and dynamic characteristics of the nanocomposites. Repol polypropylene H110MA is used as a matrix material along with the different percentages of single-walled carbon nanotubes (SWCNTs). A concept of representative volume element (RVE) is considered to study the various properties of the nanocomposite material. The carbon–carbon bond of nanotube is modeled using Tersoff–Brenner potential and represented by space frame element. The matrix material properties are tested in the laboratory which are further used to model it and represented by three-dimensional continuum elements. The interaction between nanotube and polymer matrix is modeled using “Lennard–Jones 6-12” potential represented by nonlinear spring elements. The effect of reinforcement, chirality, % volume of SWCNT, atomic vacancy defect and Stone–Wales defect on the properties of nanocomposite are investigated. To see the effect of reinforcement, the eigenvalues of the RVE are extracted for different boundary conditions. The viscoplastic behavior of the matrix material is considered and the rate-dependent characteristics of the nanocomposite are studied. The damping property of the nanocomposite material is also investigated based on the phase lag between stress and strain field by applying harmonic strain at different frequencies.

scholarly journals Constitutive modelling of arteries considering fibre recruitment and three-dimensional fibre distribution

2015 ◽  
Vol 12 (105) ◽  
pp. 20150111 ◽  
Author(s):  
Hannah Weisbecker ◽  
Michael J. Unterberger ◽  
Gerhard A. Holzapfel
Keyword(s):  
Experimental Data ◽  
Matrix Material ◽  
Three Dimensional ◽  
Collagen Fibre ◽  
Multiscale Model ◽  
Orientation Distribution ◽  
Constitutive Modelling ◽  
Collagen Fibres ◽  
Proposed Model ◽  
The Matrix

Structurally motivated material models may provide increased insights into the underlying mechanics and physics of arteries under physiological loading conditions. We propose a multiscale model for arterial tissue capturing three different scales (i) a single collagen fibre; (ii) bundle of collagen fibres; and (iii) collagen network within the tissue. The waviness of collagen fibres is introduced by a probability density function for the recruitment stretch at which the fibre starts to bear load. The three-dimensional distribution of the collagen fibres is described by an orientation distribution function using the bivariate von Mises distribution, and fitted to experimental data. The strain energy for the tissue is decomposed additively into a part related to the matrix material and a part for the collagen fibres. Volume fractions account for the matrix/fibre constituents. The proposed model only uses two parameters namely a shear modulus of the matrix material and a (stiffness) parameter related to a single collagen fibre. A fit of the multiscale model to representative experimental data obtained from the individual layers of a human thoracic aorta shows that the proposed model is able to adequately capture the nonlinear and anisotropic behaviour of the aortic layers.

Matrix cracking and the mechanical behaviour of SiC─CAS composites

1992 ◽  
Vol 437 (1899) ◽  
pp. 109-131 ◽  
Keyword(s):  
Elastic Properties ◽  
Three Dimensional ◽  
Matrix Cracking ◽  
Repeated Loading ◽  
Matrix Composites ◽  
Pull Out ◽  
Matrix Cracks ◽  
Brittle Matrix Composites ◽  
Dimensional Network ◽  
The Matrix

An experimental investigation has been carried out on the mechanical properties of unidirectional (0) 12 , (0, 90) 3S , (±45, 0 2 ) S , and (±45) 3S composites consisting of CAS glass ceramic reinforced with Nicalon SiC fibres. Measurements have been made of the elastic properties and of the tensile, compression and shear strengths of the composites, and these have been supported by a detailed study of the damage which occurs during monotonic and repeated loading. These damage studies have been carried out by means of edge replication microscopy and acoustic emission monitoring. The elastic properties of the composites are, by and large, close to the values that would be predicted from the constituent properties and lay-up sequences, but their strengths are lower than expected, and it appears that the Nicalon reinforcing fibre has been seriously degraded during manufacture. The fracture energy is much higher than predicted from observations of fibre pull-out, and it is suggested that the energy required to form a close three-dimensional network of matrix cracks could account for the high apparent toughness. The matrix cracking stress can be predicted reasonably closely by the Aveston, Cooper and Kelly model of cracking in brittle matrix composites, but it is shown that subcritical microcracks can form and/or grow at stresses well below the predicted critical values without affecting composite properties.

scholarly journals Lithium-based vertically aligned nanocomposites for three-dimensional solid-state batteries

MRS Bulletin ◽  
2021 ◽  
Vol 46 (2) ◽  
pp. 152-158 ◽  
Author(s):  
Daniel M. Cunha ◽  
Mark Huijben
Keyword(s):  
Solid State ◽  
Matrix Material ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Current Collector ◽  
The Matrix ◽  
Solid State Batteries ◽  
Vertically Aligned ◽  
Two Phases ◽  
3D Solid

AbstractPlanar two-dimensional (2D) solid-state lithium-ion batteries exhibit an undesirable energy versus power balance, which can be dramatically improved by the application of three-dimensional (3D) geometries. Current ceramics-based nanocomposites exhibit limited control of the distribution and orientation of the nanoparticles within the matrix material. However, the tailoring of functionalities by the strong coupling between the two phases and their interfaces, present in epitaxial 3D vertically aligned nanocomposites (VANs), show promising advantages over the conventional 2D planar multilayers. Although a range of epitaxial VANs have been studied in the last decade, lithium-based VANs toward battery applications have remained mostly unexplored. Interestingly, two recent studies by Qi et al. and Cunha et al. demonstrate the unique potential of lithium-based VANs toward the realization of 3D solid-state batteries with enhanced energy storage performance. In this article, we will discuss these promising results as an enhanced current collector within the cathode or as an integrated solid-state cathode-electrolyte composite. Furthermore, we will describe different design configurations that can be applied to realize self-assembled VAN-based complete 3D battery devices.

Design Optimization of a Curved Actuator with Piezoelectric Fibers

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1971-1975 ◽  
Author(s):  
Cheol Kim ◽  
Dong Yeub Lee
Keyword(s):  
Fiber Composite ◽  
Matrix Material ◽  
Three Dimensional ◽  
Linear Elastic ◽  
The Matrix ◽  
Dimensional Finite Element ◽  
Structural Responses ◽  
Piezoelectric Fiber Composite ◽  
Three Dimensional Finite Element ◽  
Piezoelectric Fiber

Piezoelectric Fiber Composite with Interdigitated Electrodes (PFCIDE) was previously introduced as an alternative to monolithic wafers with conventional electrodes for applications of structural actuation. This paper is an investigation into the performance improvement of piezoelectric fiber composite actuators by optimizing the stacking sequence and changing the matrix material. This paper presents the numerical optimization of a piezoelectric fiber/piezoelectric matrix composite actuator with IDE (PFPMIDE). Various concepts from different backgrounds, including three-dimensional linear elastic and dielectric theories, have been incorporated into the present linear piezoelectric model. To see the structural responses of the actuator integrated with the PFPMIDE, three dimensional finite element formulations were derived. Numerical analyses show larger center displacement of the curved actuator with the PFPMIDE due to optimization of the piezoelectric fiber angles. This paper presents the concept of a curved actuator that occurs naturally via thermal residual stress during the curing process, as well as the optimization of the maximum curved actuator displacement, which is accomplished using the Davidon-Fletcher-Powell (DFP) method.

Optically Transparent Nanocomposite Based on Cellulose Nanofibers from Newspapers and Polyurethane

2012 ◽  
Vol 174-177 ◽  
pp. 905-911 ◽  
Author(s):  
Xue Ting Li ◽  
Da Gang Li ◽  
Li Xu ◽  
Yu Mei Wang ◽  
Dong Liang Lin
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Cellulose Nanofibers ◽  
Three Dimensional ◽  
High Strength ◽  
Wood Powder ◽  
Sem Images ◽  
High Transparency ◽  
Dimensional Network ◽  
Optically Transparent

The goal of this paper was to develop an optically transparent nanocomposite with high strength by reinforcing polyurethane (PU) with cellulose nanofibers (CNFs) extracted from newspapers. The FE-SEM images show that through chemical and mechanical treatments, newspaper CNFs with diameters ranged from 20 to 100 nm and an aspect ratio of over 1000 were successfully obtained as well as wood powder. They were cross-linked together and formed a special three-dimensional network structure. The nanocomposite was fabricated by impregnating the CNF sheet into transparent PU resin and cured under ultraviolet. Results demonstrate that the transparency of newspaper CNF/PU nanocomposite was as high as wood CNF/PU nanocomposite. The elastic modulus and tensile strength of newspaper CNF/PU composite were increased roughly eighteen times and two times respectively while retaining the high transparency of PU, which was nearly the same with wood CNF/PU composite.

Stress Concentrations from Single-Filament Failures in Composite Materials

1969 ◽  
Vol 39 (7) ◽  
pp. 618-626 ◽  
Author(s):  
Peter Van Dyke ◽  
John M. Hedgepeth
Keyword(s):  
Matrix Material ◽  
Three Dimensional ◽  
Plastic Behavior ◽  
Two Dimensional ◽  
Failure Model ◽  
Stress Concentrations ◽  
Bond Failure ◽  
Single Filament ◽  
Concentration Problem ◽  
The Matrix

The solution of the two-dimensional, elastic, multiple-filament-failure stress concentration problem led to the treatment of three-dimensional, elastic failure models and a two-dimensional, plastic failure model where an ideally plastic behavior of the matrix material adjacent to a broken filament was assumed. Another plastic behavior is proposed wherein the bond between the broken filament and the adjacent matrix material fails completely after reaching a prescribed stress level. This failure formulation is applied to five- and seven-element-width models as well as to the infinite element case. Both the bond failure and matrix yield models are then extended to the three-dimensional cases with both square and hexagonal element configurations.

Study on the Mechanism and Properties of Activated Crumb Rubber Modified Asphalt

2011 ◽  
Vol 239-242 ◽  
pp. 191-196 ◽  
Author(s):  
Dong Wei Cao ◽  
Hai Yan Zhang
Keyword(s):  
Crosslink Density ◽  
Three Dimensional ◽  
Crumb Rubber ◽  
Experimental Results ◽  
Cross Linking ◽  
Preparation Technology ◽  
Rubber Powder ◽  
Modified Asphalt ◽  
Dimensional Network ◽  
Swelling Capacity

In this study, the activated crumb rubbers (ACR) and these ACR modified asphalts were prepared. Effects of the preparation technology of modified asphalt and properties of activated crumb rubber on performance of modified asphalt have been investigated. The activated crumb rubber powder was characterized by the Rubber NMR Crosslink Density (RNCD). The mechanism of the activated crumb rubber modified asphalt (ACRMA) was analyzed by microcosmic measures and tests such as Fluorescence Microscope (FM) etc. The experimental results indicated that the chemical and physical activating methods can improve the swelling capacity of crumb rubber in the asphalt by destroying the three-dimensional network and decreasing the cross-linking density; ACRMA have better performance compared with the crumb rubber modified asphalt. Micrograph of the ACRMA demonstrated that the structure of ACRMA is more uniform and compact, and the performances of modified asphalt were improved significantly.

scholarly journals Adsorption and release on three-dimensional graphene oxide network structures

2021 ◽  
Vol 8 (5) ◽  
pp. 201585
Author(s):  
Sunnam Kim ◽  
Sho Moriya ◽  
Sakura Maruki ◽  
Tuyoshi Fukaminato ◽  
Tomonari Ogata ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Near Infrared ◽  
Three Dimensional ◽  
Infrared Light ◽  
Cross Linking ◽  
Network Architectures ◽  
Emulsion System ◽  
Dimensional Network ◽  
Adsorption And Release ◽  
External Stimuli

In this study, three-dimensional network architectures are constructed using nano-sized graphene oxide (nGO) as the building block. The cross-linking reaction of nGO is conducted in sub-micrometre water droplets in an emulsion system to control the size of the networks by restricting the reaction space. Two types of three-dimensional GO networks with different cross-linking lengths were constructed, and their methyl orange adsorption and release behaviours were investigated under external stimuli, such as thermal treatment, ultrasonic wave treatment and near-infrared light irradiation.

Finite element prediction of stress transfer in h-BN sheet nanocomposites

2018 ◽  
Vol 9 (1) ◽  
pp. 2-16
Author(s):  
Konstantinos Spanos ◽  
Androniki Tsiamaki ◽  
Nicolaos Anifantis
Keyword(s):  
Finite Element ◽  
Hexagonal Boron Nitride ◽  
Matrix Material ◽  
Three Dimensional ◽  
Stress Transfer ◽  
Content Type ◽  
The Matrix ◽  
Element Approach ◽  
Solid Finite Elements ◽  
Heterogeneous Region

Purpose The purpose of this paper is to implement a micromechanical hybrid finite element approach in order to investigate the stress transfer behavior of composites reinforced with hexagonal boron nitride (h-BN) nanosheets. Design/methodology/approach For the analysis of the problem, a three-dimensional representative volume element, consisting of three phases, has been used. The reinforcement is modeled discretely using spring elements of specific stiffness while the matrix material is modeled as a continuum medium using solid finite elements. The third phase, the intermediate one, known as the interface, has been simulated by appropriate stiffness variations which define a heterogeneous region affecting the stress transfer characteristics of the nanocomposite. Findings The results show a good agreement with corresponding ones from the literature and also the effect of a number of factors is indicated in stress transfer efficiency. Originality/value This is the first time that such a modeling is employed in the stress transfer examination of h-BN nanocomposites.

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