scholarly journals A New Biomimetic Composite Structure with Tunable Stiffness and Superior Toughness via Designed Structure Breakage

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 636
Author(s):  
Xiaohan Wang ◽  
Dongxu Li
Keyword(s):  
Mechanical Properties ◽  
Composite Structure ◽  
Composite Structures ◽  
Structure Design ◽  
Unit Cell ◽  
Geometrical Parameters ◽  
Representative Unit Cell ◽  
New Ideas ◽  
Traditional Structures ◽  
Tunable Stiffness

Mimicking natural structures has been highly pursued recently in composite structure design to break the bottlenecks in the mechanical properties of the traditional structures. Bone has a remarkable comprehensive performance of strength, stiffness and toughness, due to the intricate hierarchical microstructures and the sacrificial bonds within the organic components. Inspired by the strengthening and toughening mechanisms of cortical bone, a new biomimetic composite structure, with a designed progressive breakable internal construction mimicking the sacrificial bond, is proposed in this paper. Combining the bio-composite staggered plate structure with the sacrificial bond-mimicking construction, our new structure can realize tunable stiffness and superior toughness. We established the constitutive model of the representative unit cell of our new structure, and investigated its mechanical properties through theoretical analysis, as well as finite element modeling (FEM) and simulation. Two theoretical relations, respectively describing the elastic modulus decline ratio and the unit cell toughness promotion, are derived as functions of the geometrical parameters and the material parameters, and validated by simulation. We hope that this work can lay the foundation for the stiffness tunable and high toughness biomimetic composite structure design, and provide new ideas for the development of sacrificial bond-mimicking strategies in bio-inspired composite structures.

scholarly journals Multiscale simulation of fullerene reinforced composite structures: From molecular dynamics to finite element continuum mechanics

2018 ◽  
Vol 188 ◽  
pp. 01013
Author(s):  
Georgios I. Giannopoulos ◽  
Stylianos K. Georgantzinos ◽  
Androniki S. Tsiamaki ◽  
Nick K. Anifantis
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Finite Element ◽  
Finite Elements ◽  
Continuum Mechanics ◽  
Mechanical Behaviour ◽  
Composite Structures ◽  
Multiscale Simulation ◽  
Unit Cell ◽  
Solid Finite Elements

The aim of the present study is to propose a multiscale computational technique for the prediction of the elastic mechanical properties of nanoreinforced composites. The proposed method utilizes a molecular dynamics (MD) based numerical scheme to capture the mechanical behaviour of the nanocomposite at nanoscale and then a classical continuum mechanics (CM) analysis based on the finite element method (FEM) to characterise the microscopic performance of the nanofilled composite material. The material under investigation is polyamide 12 (PA 12) randomly reinforced with fullerenes C60. At the first stage of the analysis, in order to capture the atomistic interfacial effects between C60 and PA 12, a very small cubic unit cell containing a C60 molecule, centrally positioned and surrounded by PA 12 molecular chains, is simulated via MD. Inter- and intra-molecular atomic interactions are described by using the Condensed Phase Optimized Molecular Potential for Atomistic Simulation Studies (COMPASS). According to the elastic properties data arisen by the MD simulations, an equivalent finite element volume with the same size as the unit cell is developed. At the second stage, a CM micromechanical representative volume element (RVE) of the C60 reinforced PA 12 is developed via FEM. The matrix phase of the RVE is discretised by using solid finite elements which represent the PA 12 mechanical behaviour while each C60 location is meshed with equivalent solid finite elements. Several multiscale simulations are performed to study the effect of the nanofiller volume fraction on the mechanical properties of the C60 reinforced PA 12 composite. Comparisons with other corresponding experimental results are attempted, where possible, to test the performance of the proposed method.

scholarly journals Influence of composite structure design on the ablation performance of ethylene propylene diene monomer composites

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 151-159
Author(s):  
Jingwen Ren ◽  
Yan Qin ◽  
Zhengwei Peng ◽  
Zhuangzhuang Li
Keyword(s):  
Thermal Insulation ◽  
Composite Structure ◽  
Composite Structures ◽  
Adhesive Layer ◽  
Liquid Structure ◽  
Structure Design ◽  
Bonding Layer ◽  
Ethylene Propylene Diene Monomer ◽  
Insulation Layer ◽  
Ethylene Propylene

Abstract By introducing functional fillers into the ethylene propylene diene monomer matrix, the anti-ablation, thermal insulation, and adhesive layer were prepared, respectively. We have studied the mechanical properties, ablation properties, thermal insulation properties, and bonding properties of different composite structures after design and analyzed the ceramic mechanism. The results showed that the content of ceramic fillers improved the thermal stability and ablation properties of anti-ablation layer composites. The formation of liquid structure can fill the hole defects and ablation pit. The foaming agent improved thermal insulation properties of the thermal insulation layer, and the strength of the bonding layer has been greatly improved. The design of the composite structure can not only reduce the density but also have an excellent thermal insulation effect. And as the thickness of the heat insulation layer increases, the heat blocking effect becomes more excellent.

The Effect of Nano-Sized Air Bubbles on the Mechanical Properties and Natural Frequencies of a Multi-Cracked Composite Bar

2017 ◽  
Vol 30 ◽  
pp. 65-84 ◽  
Author(s):  
Ahmad Al-Maharma ◽  
Naser Al-Huniti
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Composite Structure ◽  
Hybrid Composite ◽  
Composite Structures ◽  
Natural Frequencies ◽  
Volume Fraction ◽  
Multiple Cracks ◽  
Air Bubbles ◽  
The Impact

In this research, the effect of nanosized air bubbles embedded within carbon nanotubes (CNTs) coated by various thicknesses of alumina (Al2O3) reinforced epoxy resin based composite on the natural frequencies of a multi-cracked bar is investigated in details. The impact of cracks’ locations and depths within the hybrid composite structure on the natural frequency profiles is investigated. The volume fraction of CNTs is fixed to 0.5 wt. % due to the significant improvements reported in the literature when the composite is reinforced with this volume fraction of CNTs. The results of the multi-scale finite element analysis are verified by comparing with previous studies and a good agreement is shown relating to the longitudinal natural frequencies. The results of the research show that the dynamic response of cracked bar is highly sensitive to the volume fractions of nanosized air bubbles located within the composite. The results of the study supported the hypothesis that the nanosized air bubbles can be used to reduce the weight of heavy composite structures along with using of suitable coatings to improve the mechanical properties of the hybrid composite. Furthermore. The results of the study can be employed to detect multiple cracks located within similar structures like wind turbine blade (WTB) fabricated from a hybrid composite structure composed of carbon fiber reinforced modified epoxy resin which contains nanosized air bubbles and CNTs nanofillers coated by Al2O3 at different thicknesses.

Experimental Investigation of Possibilities Vacuum Infusion Technology to Produce Composite Ribs

2015 ◽  
Vol 1120-1121 ◽  
pp. 531-534
Author(s):  
Soňa Rusnáková ◽  
Ladislav Fojtl ◽  
Milan Žaludek ◽  
Alexander Čapka ◽  
Vladimír Rusnák
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Composite Structure ◽  
Composite Structures ◽  
Composite System ◽  
Lower Strength ◽  
Vacuum Infusion ◽  
One Step ◽  
Bonding Technology ◽  
Glass Reinforcement

In the present work, mechanical properties and bending stiffness of composite structures with ribs are studied. The aim of this work was making ribbed composite structures in one step, where the ribs are inserted between glass reinforcement of composite system. In practice, the ribs on the composite structure (final products) are glued, but where there is a lower strength (according to the type of surface, the surface treatment, suitable bonding technology, the type of glue) and the adhesives are relatively expensive. The production of samples was used technology of vacuum infusion under flexible foil.

scholarly journals Evaluation of the Mechanical Parameters of Ultrasonically Welded Textile Composite Structures for Protective Footwear

2019 ◽  
Vol 27 (3(135)) ◽  
pp. 99-105 ◽  
Author(s):  
Emilia Irzmańska ◽  
Katarzyna Majchrzycka ◽  
Agnieszka Adamus-Włodarczyk Adamus-Włodarczyk ◽  
Agnieszka Brochocka
Keyword(s):  
Mechanical Properties ◽  
Technological Process ◽  
Composite Structure ◽  
Composite Structures ◽  
Evaluation Method ◽  
Mechanical Resistance ◽  
Mechanical Parameters ◽  
Textile Composite ◽  
Textile Materials ◽  
Welding Spot

Textile materials are used in protective footwear due to their good mechanical and hygienic properties and to provide thermal insulation. This work presents a technological process of designing ultrasonically welded composite structures characterised by various densities of welding spots. The study involved three variants of composite structures made of three layers. The composite structures developed were tested in terms of mechanical properties and were statistically analysed in terms of the effects of welding spot density and reinforcing nonwoven thickness on the protective parameters. Inserts made of ultrasonically spot-welded textile composite structures may offer protective footwear users greater comfort in terms of mechanical resistance. The evaluation method proposed may be a useful tool in assessing textile composite structure inserts for protective footwear.

Influence of the Unit Cell Geometrical Parameter to the Mechanical Properties of Ti6Al4V Open-Porous Scaffolds Manufactured by Selective Laser Melting

2016 ◽  
Vol 851 ◽  
pp. 201-210 ◽  
Author(s):  
Ying Wang ◽  
Ji Min Chen ◽  
Yan Ping Yuan
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Pore Size ◽  
Selective Laser Melting ◽  
Geometrical Parameter ◽  
Unit Cell ◽  
Geometrical Parameters ◽  
Porous Scaffolds ◽  
Laser Melting ◽  
Element Analysis

Selective laser melting (SLM) are getting more and more established as reliable methods for producing open-porous scaffolds with accurately controlled pore size, strut size, and porosity. However, the optimal geometrical parameter of the unit cell by SLM remained unclear. In this study, we evaluated the effect of unit geometrical parameters to the mechanical properties of porous scaffolds by finite element analysis method and Mechanical testing method. Six rhombic dodecahedron unit cells were designed with different geometrical parameter and the scaffolds manufactured by SLM using Ti6Al4V. The compression testing results show that the specimens with the same pore size, the elastic modulus and the strength are increased with increasing strut size and the specimens with the same strut size, the elastic modulus and the strength are decreased with increasing strut size. The porosity can be calculated by pore size and strut size. The compression strength of the porous scaffolds is 114MPa~258MPa and the quasi-elastic gradient is 3.18Gpa~8.64Gpa, which are similar to human bone. The simulation values are different from the experiment values but the variation tendency is in accordance.

An Information-Based Design Support System for Composite Structures

2001 ◽  
Author(s):  
Xiaochun Hu ◽  
Wei Sun
Keyword(s):  
Decision Support ◽  
Design Process ◽  
Support System ◽  
Composite Structure ◽  
Material Design ◽  
Structure Design ◽  
Unit Cell ◽  
Working Environment ◽  
Design Support ◽  
Design Support System

Abstract This paper presents a framework of Information-Based Design Support System (IBDSS) for composite structure design, which is aiming at to improve the design process by alleviating the cost of obtaining the composite properties and the composite material design, automating design iterations in design process, and assisting to tailor material design. IBDSS mainly includes a database of composite unit cell, a reasoning and decision support module and a design and analysis module. The paper specifies problems in composite structure design, and describes the framework of the IBDSS, the logic structure of unit cell library, and its implementation in Java environment with SQL. The reasoning and decision support module with blackboard architecture and the working environment of IBDSS for Internet based design are also presented.

Composite Structure Optimization Design System Based on Grid Technology

2007 ◽  
Vol 334-335 ◽  
pp. 453-456
Author(s):  
Wen Yuan Cheng ◽  
De Gang Cui ◽  
Yan Chang ◽  
Xiang Hui Xie
Keyword(s):  
Genetic Algorithm ◽  
Composite Structure ◽  
Composite Structures ◽  
Optimization Design ◽  
Structure Design ◽  
Design System ◽  
Grid Technology ◽  
Great Effort ◽  
Optimization Approach ◽  
Element Analysis

In the traditional iterative design process for composite structures, it is difficult to achieve an optimal solution even though a great effort is made. A genetic optimization system based on grid technology offers an automatic and efficient approach for composite structure redesign and optimization. A genetic algorithm system, which integrates Genetic Algorithm Optimization (GAO) software and a Finite Element Analysis (FEA) based commercial package, has been developed as a tool for composite structure design and analysis. The GAO is capable of tailoring large number of composite design variables and taking the time-consuming FEA results to calculate objective function value and conduct optimization in high accuracy. By operating the system employing the Grid technology and Artificial Neural Network (ANN) method, significant time saving in numerical analysis can be achieved. A user friendly interface has also been built in the system. In the paper, aeroelastic tailoring of a composite wing has been taken as a numerical example to demonstrate the optimization approach. The numerical results show that an optimal design has been achieved to meet the design requirement.

FIRE RESISTACE OF SHEAR CONNECTORS FOR COMPOSITE BEAMS

2020 ◽  
Vol 92 (6) ◽  
pp. 59-65
Author(s):  
G.P. TONKIH ◽  
◽  
D.A. CHESNOKOV ◽  
◽  
Keyword(s):  
Fire Resistance ◽  
Composite Structure ◽  
Composite Structures ◽  
Composite Beams ◽  
Design Codes ◽  
Connection Strength ◽  
Shear Connectors ◽  
Shear Connection ◽  
Capacity Reduction ◽  
Russian Research

Most of Russian research about composite structure fire resistance are dedicated to the composite slab behavior. The composite beams fire resistance had been never investigated in enough volume: the temperature evaluation within the scope of the actual Russian design codes leads to the significant reduction in the shear connection strength. Meanwhile, there no correlation between the strength decreasing and type of the shear connection. The article provides an overview of the relevant researches and offers some approaches which could take into account bearing capacity reduction of the shear connectors within composite structures design.

scholarly journals Anti-Inflammatory Properties of Injectable Betamethasone-Loaded Tyramine-Modified Gellan Gum/Silk Fibroin Hydrogels

Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1456
Author(s):  
Isabel Matos Oliveira ◽  
Cristiana Gonçalves ◽  
Myeong Eun Shin ◽  
Sumi Lee ◽  
Rui Luis Reis ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Mechanical Properties ◽  
Silk Fibroin ◽  
Therapeutic Efficacy ◽  
Composite Structures ◽  
Gelation Time ◽  
Polymeric Materials ◽  
Gellan Gum ◽  
Traditional Use

Rheumatoid arthritis is a rheumatic disease for which a healing treatment does not presently exist. Silk fibroin has been extensively studied for use in drug delivery systems due to its uniqueness, versatility and strong clinical track record in medicine. However, in general, natural polymeric materials are not mechanically stable enough, and have high rates of biodegradation. Thus, synthetic materials such as gellan gum can be used to produce composite structures with biological signals to promote tissue-specific interactions while providing the desired mechanical properties. In this work, we aimed to produce hydrogels of tyramine-modified gellan gum with silk fibroin (Ty–GG/SF) via horseradish peroxidase (HRP), with encapsulated betamethasone, to improve the biocompatibility and mechanical properties, and further increase therapeutic efficacy to treat rheumatoid arthritis (RA). The Ty–GG/SF hydrogels presented a β-sheet secondary structure, with gelation time around 2–5 min, good resistance to enzymatic degradation, a suitable injectability profile, viscoelastic capacity with a significant solid component and a betamethasone-controlled release profile over time. In vitro studies showed that Ty–GG/SF hydrogels did not produce a deleterious effect on cellular metabolic activity, morphology or proliferation. Furthermore, Ty–GG/SF hydrogels with encapsulated betamethasone revealed greater therapeutic efficacy than the drug applied alone. Therefore, this strategy can provide an improvement in therapeutic efficacy when compared to the traditional use of drugs for the treatment of rheumatoid arthritis.

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