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Optimisation of hybrid high-modulus/high-strength carbon fibre
reinforced plastic composite driveshaftsOriginal Research ArticleMaterials & Design, Volume 46,April 2013, Pages 88-100
O. Montagnier, Ch. Hochard
Abstract
This study deals with the optimisation of hybrid composite drive shafts operating at subcritical or supercritical speeds,
using a genetic algorithm. A formulation for the flexural vibrations of a composite drive shaft mounted on viscoelastic
supports including shear effects is developed. In particular, an analytic stability criterion is developed to ensure the
integrity of the system in the supercritical regime. Then it is shown that the torsional strength can be computed with
the maximum stress criterion. A shell method is developed for computing drive shaft torsional buckling. The
optimisation of a helicopter tail rotor driveline is then performed. In particular, original hybrid shafts consisting of high-
modulus and high-strength carbon fibre reinforced epoxy plies were studied. The solutions obtained using the method
presented here made it possible to greatly decrease the number of shafts and the weight of the driveline under
subcritical conditions, and even more under supercritical conditions. This study yielded some general rules for
designing an optimum composite shaft without any need for optimisation algorithms.
Article Outline
Nomenclature
1.Introduction
2.Design aspects
o 2.1.Flexural vibration analysis
o 2.2.Torsional vibration analysis
o 2.3.Failure strength analysis
o 2.4.Torsional buckling analysis
o
2.5.Driveline mass
3.Shaft optimisation using a genetic algorithm
o 3.1.Individual
o 3.2.Constraints and fitness
o 3.3.The genetic algorithm method
o
3.3.1.Initialisation
3.3.2.Elitism
3.3.3.Scaling, selection and crossover
3.3.4.Mutation
4.Case study
o 4.1.Subcritical shaft optimisation
o 4.2.Supercritical shaft optimisation
5.Conclusion
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Appendix A.Torsional buckling equations
References
Bending of fibre-reinforced thermoplastic sheetsOriginal Research Article
Composites Manufacturing, Volume 6, Issues 34, 1995, Pages 177-187
T.A. Martin, D. Bhattacharyya, I.F. Collins
Abstract
When forming continuous fibre-reinforced thermoplastic (CFRT) sheets into three-dimensional components, interply
shearing may be necessary in order to accommodate the out-of-plane bending because the fibres severely constrain
the deformation along the fibre directions within their planes. Furthermore, thermoforming takes place at elevated
temperatures so that the molten matrix polymer becomes fluid. These two factors are of prime importance in
analysing any forming process with thermoplastic composite materials. This paper examines the process of forming
unidirectional Plytron (a glass fibre-reinforced polypropylene composite, originally developed by ICI, UK) sheets into
V-bends at a constant elevated temperature, and compares the experimental results with those predicted by an
analytical model for plane strain bending of an incompressible Newtonian fluid reinforced with a single family of
inextensible fibres. The shape of a strip as it is formed, the effects of temperature and forming speed on the formingloads are also investigated. A major conclusion from this study is that Plytron sheets demonstrate a viscoelastic
response when formed within their melting range and the degree of elasticity is increased by reducing the
temperature, which, in turn, can reduce the fibre instability. The theoretical model provides useful results for
evaluating the effective longitudinal viscosity of the composite sheet, the effects of forming speed and punch
geometry on the bending stresses and also highlights the limitations of a Newtonian fluid model in comparison with
the actual material response.
Damage behavior of fiber reinforced composite plates subjected to drop weight impactsOriginal Research
Article
Composites Science and Technology, Volume 66, Issue 1, January 2006, Pages 61-68
Ramin Hosseinzadeh, Mahmood Mehrdad Shokrieh, Larry Lessard
Abstract
Fiber reinforced materials are widely used in many industrial structures including automotive, aviation, and civil due to
their lower weights compared to metal structures. Full-composite body structures, especially in automotive and
aviation applications, are becoming a proper replacement for current metal ones. For this reason, damage of such
structures subjected to impact is a crucial case study in current research. The typical types of damages are mainly
caused during production, repair, maintenance, or by particle crashes during function, and collisions between
different structures. In this paper, four different fiber reinforced composite plates are studied after being impacted by a
standard drop weight with different impact energies and moments. The damage zones are studied by ultra-sonic non-
destructive inspection. Carbon fiber reinforced composite plates show the best structural behavior under low velocity
impacts meanwhile carbon/glass fiber reinforced (hybrid) plates show suitable behavior under high impact energy.
Finally, all the plates are modeled using ANSYS LS DYNA V6.1 under similar conditions to those of the tests. The
damage zone shapes derived from software modeling do not show very good coincidence with those resulting from
the tests. However, the software is able to predict the threshold of damage as it is verified well by test results.
Article Outline
1.Introduction
2.Test configuration
3.Inspection method
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4.Glass fiber woven composites
5.Carbon fiber reinforced composites
6.Hybrid composites
7.Test results
8.Software modeling
9.Summary
References
Composition of Fiber Reinforced Composites
Common fiber reinforced composites are composed of fibers and a matrix. Fibers are the
reinforcement and the main source of strength while the matrix 'glues' all the fibers
together in shape and transfers stresses between the reinforcing fibers. Sometimes, fillers
or modifiers might be added to smooth manufacturing process, impart special properties,
and/or reduce product cost.
Fibers of Fiber Reinforced Composites
The primary function of the fibers is to carry the loads along their longitudinal directions.
Common fiber reinforcing agents include
Aluminum, Aluminum oxide, Aluminum silica
Asbestos
Beryllium, Beryllium carbide, Beryllium oxide
Carbon (Graphite)
Glass (E-glass, S-glass, D-glass)
Molybdenum
Polyamide (Aromatic polyamide, Aramid), e.g., Kevlar 29 and Kevlar 49
Polyester
Quartz (Fused silica)
Steel
Tantalum
Titanium
Tungsten, Tungsten monocarbide
Matrix of Fiber Reinforced Composites
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The primary functions of the matrix are to transfer stresses between the reinforcing fibers
(hold fibers together) and protect the fibers from mechanical and/or environmental
damages. A basic requirement for a matrix material is that its strain at break must be larger
than the fibers it is holding.
Most matrices are made of resins for their wide variation in properties and relatively low
cost. Common resin materials include
Resin Matrix
o Epoxy
o Phenolic
o Polyester
o Polyurethane
o Vinyl Ester
Among these resin materials, polyesters are the most widely used. Epoxies, which have
higher adhesion and less shrinkage than polyesters, come in second for their higher costs.
Although less common, non-resin matrices (mostly metals) can still be found in applications
requiring higher performance at elevated temperatures, especially in the defense industry.
Metal Matrix
o
Aluminumo Copper
o Lead
o Magnesium
o Nickel
o Silver
o Titanium
Non-Metal Matrix
o Ceramics
Modifiers of Fiber Reinforced Composites
The primary functions of the additives (modifiers, fillers) are to reduce cost, improve
workability, and/or impart desired properties.
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Cost Reduction:
o Low cost to weight ratio, may fill up to 40% (65% in some cases) of the total
weight
Workability Improvement:
o Reduce shrinkage
o Help air release
o Decrease viscosity
o Control emission
o Reduce coefficient of friction on surfaces
o Seal molds and/or guide resin flows
o Initiate and/or speed up or slow down curing process
Property Enhancement:
o Improve electric conductivity
o Improve fire resistance
o Improve corrosion resistance
o Improve ultraviolet resistance
o Improve surface toughness
o Stabilize heat transfer
o Reduce tendency of static electric charge
o Add desired colors
Common materials used as additives include
Filler Materials:
o Feldspar
o Glass microspheres
o Glass flakes
o Glass fibers, milled
o Mica
o Silica
o Talc
o Wollastonite
o Other microsphere products
Modifier Materials:
o Organic peroxide, e.g., methylethylketone peroxide (MEKP)
o Benzoyl peroxide
o Tertiary butyl catechol (TBC)
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o Dimethylaniline (DMA)
o Zinc stearate, waxes, silicones
o Fumed silica, clays
Multiphase layout optimization for fiber reinforced composites considering a damage modelOriginal Research
Article
Engineer ing Structures, Volume 49, Ap ril 2013, Pages 202-220
Junji Kato, Ekkehard Ramm
Abstract
The present study addresses an optimization strategy for fiber reinforced composites, specifically Fiber Reinforced
Concrete (FRC) with a complex failure mechanism resulting from material brittleness of both matrix and fibers and
also from the nonlinear interfacial behavior between those constituents. A prominent objective for this kind of
composite is the improvement of ductility. The entire structural response of this material strongly depends on three
factors, (i) material layout of fiber on a small scale, (ii) fiber geometry on the macroscopic structural level, and (iii)
material parameters of interface between matrix and fiber.
The purpose of the present study is to improve the structural ductility of FRC by applying optimization; in the
formulation not only the optimal material layout of fibers on the small scale but also the global fiber geometry are
determined simultaneously. The proposed method is achieved by combining multiphase material optimization and
material shape optimization, separately introduced by Kato et al. and Kato and Ramm , respectively.
For the optimization problem a gradient-based optimization scheme is assumed. A method of moving asymptotes
(MMA) is applied because of its numerically high efficiency and robustness. The performance of the proposed
method is demonstrated by a series of numerical examples and compared with pure material shape optimization. It is
verified that the proposed method gives more efficient results than the individual material shape optimization and that
the structural ductility can be substantially improved.
Article Outline
1.Introduction
o 1.1.Overview
2.Applied material models
o 2.1.Material model for constituents concrete and fiber
o 2.2.Material model for interface
3.Background: multiphase material and material shape optimization
o 3.1.Multiphase material optimization
o 3.2.Material shape optimization
4.Multiphase layout optimization
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o 4.1.Basic concept
o 4.2.Two-phase fiber
o 4.3.Three-phase fiber
o 4.4.Interpolation rule for interface
5.Embedded reinforcement element
o 5.1.Kinematical assumption for interface between concrete and fiber
6.Finite element formulation of FRC
o 6.1.Discretized principle virtual work
o 6.2.Element matrices
7.Structural optimization of FRC
o 7.1.Optimization problem
o 7.2.Equilibrium conditions and total derivative of design function
8.Sensitivity analysis
o 8.1.Overview of sensitivity analysis
o 8.2.Gradients of constitutive equations
o 8.3.Sensitivity for explicit term of objective function
o 8.4.Calculation of sensitivity coefficients
o
8.5.Total sensitivity
9.Numerical examples
o 9.1.Material shape optimization vs. multiphase layout optimization
o
9.1.1.Deep beam
9.1.2.Splitting plate
o 9.2.L-shape plate
10.Conclusions
Acknowledgement
Appendix A.List of symbols
References
Hybrid natural and glass fibers reinforced polymer composites material selection using Analytical Hierarchy
Process for automotive brake lever designOriginal Research Article
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Materials & Design, Volume 51, October 2013, Pages 484-492
M.R. Mansor, S.M. Sapuan, E.S. Zainudin, A.A. Nuraini, A. Hambali
Abstract
Due to recent trend and increasing awareness towards sustainable product design, natural based fiber materials are
gaining a revival popularity to replace synthetic based fiber in the formulation of composites especially for automotive
structural and semi structural applications. In this paper, the Analytical Hierarchy Process (AHP) method was utilized
in the selection of the most suitable natural fiber to be hybridized with glass fiber reinforced polymer composites for
the design of a passenger vehicle center lever parking brake component. Thirteen (13) candidate natural based fiber
materials for the hybridization process were selected and analyzed to determine their overall scores in three (3) main
performance indices according to the component product design specifications. Using the AHP method, the kenaf
bast fiber yields the highest scores and was selected as the best candidate material to formulate the hybrid polymer
composites for the automotive component construction. Sensitivity analysis was also performed and results show that
kenaf bast fiber emerged as the best candidate material in two out of three simulated scenarios, which further
validates the results gained through the AHP method.
Article Outline
1.Introduction
2.Product design specifications
o 2.1.Product design specification for automotive parking brake lever
3.Material selection of hybrid natural and glass fibers reinforced polymer composites using AHP: a case study on
automotive parking brake lever component
o 3.1.Overall material selection methodology using AHP
o 3.2.Development of AHP hierarchical framework
o 3.3.Performing judgment using pair-wise comparison
o 3.4.Synthesizing pair-wise judgments and calculating priority vectors
o 3.5.Performing consistency analysis using consistency ratio
o 3.6.Final AHP hybrid polymer composites material selection results
o 3.7.Results verification using sensitivity analysis
4.Conclusion
Acknowledgments
References
Numerical investigation of the effects of drill geometry on drilling induced delamination of carbonfiber
reinforced compositesOriginal Research Article
Composite Structures, Volume 105, November 2013, Pages 126-133
Ozden Isbilir, Elaheh Ghassemieh
Abstract
Drilling is a major process in the manufacturing of holes required for the assemblies of composite laminates in
aerospace industry. Simulation of drilling process is an effective method in optimizing the drill geometry and process
parameters in order to improve hole quality and to reduce the drill wear. In this research we have developed three-
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dimensional (3D) FE model for drilling CFRP. A 3D progressive intra-laminar failure model based on the Hashins
theory is considered. Also an inter-laminar delamination model which includes the onset and growth of delamination
by using cohesive contact zone is developed. The developed model with inclusion of the improved delamination
model and real drill geometry is used to make comparison between the step drill of different stage ratio and twist drill.
Thrust force, torque and work piece stress distributions are estimated to decrease by the use of step drill with high
stage ratio. The model indicates that delamination and other workpiece defects could be controlled by selection ofsuitable step drill geometry. Hence the 3D model could be used as a design tool for drill geometry for minimization of
delamination in CFRP drilling.
Article Outline
1.Introduction
2.Numerical procedures
o 2.1.Stress model
o 2.2.Progressive failure model (intra-laminar failure)
o 2.3.Progressive delamination model (inter-laminar failure)o 2.4.Finite element model of drilling
3.Experimental procedure
4.Results and discussion
o 4.1.Verification of force and torque
o 4.2.Verification of delamination prediction
o 4.3.Effects of geometry on thrust force and torque
o 4.4.Effects of geometry on damage and delamination
o 4.5.Stress distribution
5.Conclusions
Acknowledgements
References
Design of newly fabricated tribological machine for wear and frictional experiments under dry/wet
conditionOriginal Research Article
Materials & Design, Volume 48, June 2013, Pages 2-13
B.F. Yousif
Abstract
Nowadays, there is demand to evaluate tribological performance of new engineering materials using different
techniques. Various laboratory tribo-machines have been designed and fabricated such as Pin-on-Disc (POD), ASTM
G99, Block-on-Ring (BOR), ASTM G77 or G137-953, Dry Sand Rubber Wheel (DSRW), ASTM G655, Wet Sand
Rubber Wheel (WSRW), ASTM G105, and sand/steel wheel test under wet/dry conditions (ASTM B611). A concept
of integrating more than one tribo-technique at different contact mechanisms (line or area) working simultaneously
under same test condition against same material is introduced in a current designed machine. Different wear modes
(adhesive, two-body-abrasive, three-body-abrasive, under dry, lubricated, or slurry conditions) can be conducted on
the same machine. Results of adhesive wear, friction and interface temperature of glass fibre reinforced polyester
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composite under wet/dry contact condition are reported at 50 N load for different sliding speeds (2.87.8 m/s) using
the new machine. Weight loss and friction coefficient of the composite were substantially influenced by introducing
water as lubricant. Additionally, the contact condition has the high influence key on the wear and frictional
performance of the composite.
Article Outline
1.Introduction
2.New tribological apparatus configurations
3.Material preparation and experimental procedure
o 3.1.Preparation of samples
o
3.1.1.Dry adhesive tests
3.1.2.Wet adhesive tests
4.Results and discussion
o 4.1.Dry contact condition
o 4.2.Wet contact condition
o 4.3.Surface observations
5.Conclusion
References
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