Fabrication of Composite Materials from Fibrous Precursors Using Paper Making Procedures

1990 ◽  
Vol 197 ◽  
Author(s):  
J. N. Zabasajja ◽  
Soonho Ahn ◽  
Tony Wu ◽  
A. Krishnagopalan ◽  
B. J. Tatarchuk
Keyword(s):  
Composite Materials ◽  
Composite Structure ◽  
Composite Structures ◽  
Structural Integrity ◽  
High Energy ◽  
High Energy Density ◽  
Kinetic Measurements ◽  
Paper Making ◽  
Bonded Composite ◽  
Sinter Bonding

ABSTRACTNovel composite materials have been fabricated from fibrous precursors using paper making procedures. Small metal fibers (2 μm in diameter) and carbon fiber bundles (20 μm in diameter) were combined with cellulose (as the binding agent) into an interwoven paper preform. The composite paper preform was then sintered at high temperatures in a controlled atmosphere, subsequently removing the cellulose and forming a sinter-bonded composite structure. The sinter bonding of the metal locked the metal fibers and provided high mechanical flexibility and structural integrity to the resulting composite structure. The composite structures were characterized using scanning electron microscopy, electrochemical and kinetic measurements. The optimization of these structures for high energy density applications was demonstrated through these measurements.

scholarly journals Defects and uncertainties of adhesively bonded composite joints

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Sadik Omairey ◽  
Nithin Jayasree ◽  
Mihalis Kazilas
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Production Efficiency ◽  
Adhesive Bonding ◽  
Detection Methods ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Wide Range ◽  
Bonded Composite

AbstractThe increasing use of fibre reinforced polymer composite materials in a wide range of applications increases the use of similar and dissimilar joints. Traditional joining methods such as welding, mechanical fastening and riveting are challenging in composites due to their material properties, heterogeneous nature, and layup configuration. Adhesive bonding allows flexibility in materials selection and offers improved production efficiency from product design and manufacture to final assembly, enabling cost reduction. However, the performance of adhesively bonded composite structures cannot be fully verified by inspection and testing due to the unforeseen nature of defects and manufacturing uncertainties presented in this joining method. These uncertainties can manifest as kissing bonds, porosity and voids in the adhesive. As a result, the use of adhesively bonded joints is often constrained by conservative certification requirements, limiting the potential of composite materials in weight reduction, cost-saving, and performance. There is a need to identify these uncertainties and understand their effect when designing these adhesively bonded joints. This article aims to report and categorise these uncertainties, offering the reader a reliable and inclusive source to conduct further research, such as the development of probabilistic reliability-based design optimisation, sensitivity analysis, defect detection methods and process development.

scholarly journals The development of an advanced composite structure using evolutionary design methods

2009 ◽  
Author(s):  
◽  
David Van Wyk
Keyword(s):  
Composite Materials ◽  
Composite Structure ◽  
Composite Structures ◽  
Empirical Method ◽  
Optimum Shape ◽  
Evolutionary Design ◽  
Structural Optimisation ◽  
Design For Manufacture ◽  
Advanced Composite ◽  
Evolutionary Optimisation

The development of an evolutionary optimisation method and its application to the design of an advanced composite structure is discussed in this study. Composite materials are increasingly being used in various fields, and so optimisation of such structures would be advantageous. From among the various methods available, one particular method, known as Evolutionary Structural Optimisation (ESO), is shown here. ESO is an empirical method, based on the concept of removing and adding material from a structure, in order to create an optimum shape. The objective of the research is to create an ESO method, utilising MSC.Patran/Nastran, to optimise composite structures. The creation of the ESO algorithm is shown, and the results of the development of the ESO algorithm are presented. A tailfin of an aircraft was used as an application example. The aim was to reduce weight and create an optimised design for manufacture. The criterion for the analyses undertaken was stress based. Two models of the tailfin are used to demonstrate the effectiveness of the developed ESO algorithm. The results of this research are presented in the study.

A Review of Damage Tolerant Design, Certification and Repair in Metals Compared to Composite Materials

2014 ◽  
Vol 891-892 ◽  
pp. 1597-1602 ◽  
Author(s):  
Nabil Chowdhury ◽  
Wing Kong Chiu ◽  
John Wang
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Failure Modes ◽  
Structural Integrity ◽  
Fiber Reinforced Polymers ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Repair Efficiency ◽  
Mechanically Fastened ◽  
Damage Tolerant

A review of some of the various fatigue models introduced over the years for both metallic materials, in particular aluminium alloys followed by fatigue and durability concerns associated with composite materials. The move towards light weight and high stiffness structures that have good fatigue durability and corrosion resistance has led to the rapid move from metal structures to composite structures. With this brings the added concern of certifying new components as the damage mechanisms and failure modes in metals differ significantly than composite materials such as carbon fiber reinforced polymers (CFRP). The certification philosophy for composites must meet the same structural integrity, safety and durability requirements as that of metals. Hence this is where the challenge now lies. Substantial work has been conducted in the reparability of composite structures through bonding using various adherend thicknesses and joint types and has been shown to have higher durability than mechanically fastened repairs for thin adherends however these are currently unacceptable repair methods as they cannot be certified. Repairs are designed on the basis that the repair efficiency can be predicted and should be designed conservatively with respect to the various failure modes and include the surrounding structure.

An Approach to Enhancement of Conductivity in Composite Material Using Nanotechnology

2006 ◽  
Author(s):  
Vivian T. Dang ◽  
Russ Maguire ◽  
Robab Safa-Bakhsh
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Composite Structure ◽  
Composite Structures ◽  
Test Methods ◽  
Commercial Aircraft ◽  
Nano Technology ◽  
Novel Approaches ◽  
Non Destructive ◽  
Potential Integration

This review documents possible developments using Nano technology to enhance electromagnetic effects (EME) and identifies the potential integration on the composite structures for the next generation composite commercial aircraft. First, developments using Nano technology as a source to enhance the EME of the composite will be discussed. These developments include computational modeling of Nano-filled composites to predict certain properties and behaviors of Nano-enhanced materials, test methods for non-destructive examination of Nano-modified materials, and other novel approaches to resolve the challenges of increasing conductivity in composite materials. Next, the details of the potential impacts of using Nano technology for increasing conductivity will be outlined. Finally, the implementation of a Nano-enhanced material on the composite structure will be described.

scholarly journals Piezoelectric Impedance-Based Non-Destructive Testing Method for Possible Identification of Composite Debonding Depth

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 621 ◽  
Author(s):  
Wongi S. Na ◽  
Jongdae Baek
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Structural Integrity ◽  
Structural Safety ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Electromechanical Impedance ◽  
Testing Method ◽  
Piezoelectric Impedance ◽  
Non Destructive

Detecting the depth and size of debonding in composite structures is essential for assessing structural safety as it can weaken the structure possibly leading to a failure. As composite materials are used in various fields up to date including aircrafts and bridges, inspections are carried out to maintain structural integrity. Although many inspection methods exist for detection damage of composites, most of the techniques require trained experts or a large equipment that can be time consuming. In this study, the possibility of using the piezoelectric material-based non-destructive method known as the electromechanical impedance (EMI) technique is used to identify the depth of debonding damage of glass epoxy laminates. Laminates with various thicknesses were prepared and tested to seek for the possibility of using the EMI technique for identifying the depth of debonding. Results show promising outcome for bringing the EMI technique a step closer for commercialization.

scholarly journals Structural integrity of engineering composite materials: a cracking good yarn

2016 ◽  
Vol 374 (2071) ◽  
pp. 20160057 ◽  
Author(s):  
Peter W. R. Beaumont ◽  
Costas Soutis
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Large Scale ◽  
Structural Integrity ◽  
High Efficiency ◽  
Human Life ◽  
Engineering Structures ◽  
Catastrophic Fracture ◽  
Materials Used ◽  
Integrity Analysis

Predicting precisely where a crack will develop in a material under stress and exactly when in time catastrophic fracture of the component will occur is one the oldest unsolved mysteries in the design and building of large-scale engineering structures. Where human life depends upon engineering ingenuity, the burden of testing to prove a ‘fracture safe design’ is immense. Fitness considerations for long-life implementation of large composite structures include understanding phenomena such as impact, fatigue, creep and stress corrosion cracking that affect reliability, life expectancy and durability of structure. Structural integrity analysis treats the design, the materials used, and figures out how best components and parts can be joined, and takes service duty into account. However, there are conflicting aims in the complete design process of designing simultaneously for high efficiency and safety assurance throughout an economically viable lifetime with an acceptable level of risk. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

Composite Fracture: Getting to the Heart of the Matter

2011 ◽  
Vol 471-472 ◽  
pp. 1-6
Author(s):  
Peter W.R. Beaumont
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Structural Integrity ◽  
Constitutive Models ◽  
Process Variables ◽  
Material Systems ◽  
New Knowledge ◽  
Structural Composite ◽  
Successful Design ◽  
Materials Used

The demands made on structural composite materials in modern design are increasingly stringent. Greater performance, lower costs, increased reliability and safety all require that the design engineer knows more and more of the material systems available. Bringing together new knowledge contained in constitutive models of continuum design and empirical information from a girth of experience is proving to be difficult because the number of service and process variables required for sophisticated, optimal design is becoming increasingly larger. Understanding Structural Integrity (SI) provides the key to the successful design, certification, and safety of large composite structures and engineering composite materials. This is because SI analysis treats simultaneously the design, the materials used, figures out how best components and parts are joined, and takes service duty into account. But predicting precisely where a crack will develop in a material under stress and exactly when in time catastrophic failure of the structure will occur remains an unsolved mystery.

scholarly journals Multiscale Analysis of Multilayer Composite Pipes

2018 ◽  
Author(s):  
DC Pham
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Offshore Platforms ◽  
Fiber Reinforced ◽  
Stick Slip ◽  
Flexible Fiber ◽  
Non Linear ◽  
Bonded Composite ◽  
Laminate Cylinder ◽  
Composite Pipes

The use of composite materials in offshore applications has constantly increased towards the development of deepwater technology and ultra-deepwater feasibility. Cylindrical composite pipes are the most principal components in floating and offshore platforms. Composite pipes could be grouped into bonded and unbonded structures. Typical bonded composite structures comprise a core angle ply laminate cylinder sandwiched between an inner liner and an outer liner made of elastomer or metal alloys. On the other hand, unbonded composite pipes such as flexible pipes in floating platforms consist of multiple metallic and polymeric layers, among which tensile wires play essential roles in providing axial and bending stiffnesses. The flexibility in motion of each layers of the unbonded composite pipe and the complexity in their geometries and materials make the analysis of unbonded composite structures very challenging. In this work, multiscale non-linear analyses of unbonded flexible risers are carried out and the non-linear behaviors of individual riser layers as well as stick-slip mechanisms between them are studied. In addition, the work also discusses the potential of flexible fiber-reinforced pipe where metal amour strips may be replaced by fiber-reinforced composite materials to significantly enhance the structural performance of conventional pipe.

scholarly journals Designing a hybrid electrode toward high energy density with a staged Li+ and PF6− deintercalation/intercalation mechanism

2020 ◽  
Vol 117 (6) ◽  
pp. 2815-2823 ◽  
Author(s):  
Junnan Hao ◽  
Fuhua Yang ◽  
Shilin Zhang ◽  
Hanna He ◽  
Guanglin Xia ◽  
...  
Keyword(s):  
Energy Density ◽  
Structural Integrity ◽  
Electrode Materials ◽  
High Capacity ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Ex Situ ◽  
Discharge Process ◽  
Voltage Range

Existing lithium-ion battery technology is struggling to meet our increasing requirements for high energy density, long lifetime, and low-cost energy storage. Here, a hybrid electrode design is developed by a straightforward reengineering of commercial electrode materials, which has revolutionized the “rocking chair” mechanism by unlocking the role of anions in the electrolyte. Our proof-of-concept hybrid LiFePO4 (LFP)/graphite electrode works with a staged deintercalation/intercalation mechanism of Li+ cations and PF6− anions in a broadened voltage range, which was thoroughly studied by ex situ X-ray diffraction, ex situ Raman spectroscopy, and operando neutron powder diffraction. Introducing graphite into the hybrid electrode accelerates its conductivity, facilitating the rapid extraction/insertion of Li+ from/into the LFP phase in 2.5 to 4.0 V. This charge/discharge process, in turn, triggers the in situ formation of the cathode/electrolyte interphase (CEI) layer, reinforcing the structural integrity of the whole electrode at high voltage. Consequently, this hybrid LFP/graphite-20% electrode displays a high capacity and long-term cycling stability over 3,500 cycles at 10 C, superior to LFP and graphite cathodes. Importantly, the broadened voltage range and high capacity of the hybrid electrode enhance its energy density, which is leveraged further in a full-cell configuration.

scholarly journals METHODS OF MODELING OF COMPOSITE MATERIALS AND COMPOSITE STRUCTURES ON «LIRA-SAPR»

2017 ◽  
Vol 1 (48) ◽  
pp. 129-137
Author(s):  
M. S. Barabash ◽  
I. V. Genzerskyi ◽  
А. V. Pikul А.V. ◽  
О. Yu Bashynska
Keyword(s):  
Numerical Modeling ◽  
Composite Material ◽  
Composite Materials ◽  
Composite Structure ◽  
Software Package ◽  
Composite Structures ◽  
Frame Structure ◽  
Structural Reinforcement ◽  
Modeling Process ◽  
Metal Casing

This paper provides detailed suggestions for the process of structural reinforcement modeling by composite materials on the software package «LIRA-SAPR». It also provides the implementation of bearing capacity checks for reinforced elements on the program called «ESPRI». The article offers an algorithm for calculation of  the construction objects in case of design situation changing, considering the modeling of the composite structure reinforcement. It considered the modeling process of reinforcement of structures using classical methods, such as using of metal casing. It also investigated a numerical modeling example of the frame structure reinforcement, with the selection and verification of the composite material.

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