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Characterization of carbon fiber reinforced plastics to achieve optimum mechanical properties to be used in automotive applications
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Characterization and failure study of Chopped Carbon Fiber Reinforced Polymer (CCFRP)
Composite for automotive applications
Geo Jose
Objective To develop a Chopped Carbon fiber reinforced
PMC with mechanical properties and processing significantly superior to current Carbon fiber SMC materials, in order to expand its application for automotive light-weighting by attaining better strength, serviceability, durability and cost-effectiveness
Why? Anisotropic mechanical properties (quasi-
isotropic laminate composites) limit the application
high raw material costs and long cycle times Reliable material performance and crash
modeling routines need to be developed – QUALITY
Recyclability will soon be a need Composites to be challenged by other
lightweight materials (Mg, Al, HS Steels)
Discontinuous fiber thermoplastics
FeaturesMass production with reasonable performanceReduces cost/partIsotropic Complex geometries possible/formabilityrandom nature of the fibers limits the mechanical properties to 20-40% of an aligned material [16]Recyclability
Adapted from Fig.16.8, Callister 7e.
Discontinuous random 2D fibers
ChallengesEnsure process repeatability (Proper mixing/orientation)Consistent mechanical properties over the bulk of the composite material (Reduce voids and imperfections)Cycle time reductionImprove mechanical performance Identifying critical fiber lengthRetaining mechanical properties after recycling
Mechanical performance vs. production volume vs. manufacturing process. From an internal report supplied by Hexcel, Duxford.
Factors affecting the mechanical behavior Component properties
Structure and mechanical behavior of matrix, fiber and filler. Chemical composition, purity, surface free energy…
Interfacial interactions Surface treatments on fibers
Composition Resultant composite behavior is a function of the %volume of matrix,
fiber and filler. (Garoushi, Lassila & Vallittu 2006) Structure
Orientation (Jules et al.) Aggregation (Distribution) (Lei, Zhang & Liu 2012) Length/aspect ratio of fiber (Hashimoto et al. 2012; Fu & Lauke 1996) Shape of fiber
Processing conditions Fabrication process (Joseph, Joseph & Thomas 1999) Process parameter (Kiran et al. 2011; Raunija et al. 2014; Wu et al.
2013)
Key Technical Challenges Obtain Mechanical Properties for Structural Automotive
applications Dispersion of Fibers
Chopping fibers Hybrid blends
Fiber-Matrix Compatibility Surface treatments?
Moisture Absorption Ensure process repeatability (Proper mixing/orientation) Consistent mechanical properties over the bulk of the
composite material (Reduce voids and imperfections) Cycle time reduction Retaining mechanical properties after recycling
Addressing the Challenges Composite - A structural material that gains
its strength from a combination of complementary materials
1. Modify the reinforcement2. Modify the resin3. Modify the manufacturing process
Approach Investigate the deformation behavior and fiber/matrix
adhesion of the composites at different volume fractions and fiber lengths Influence of these parameters on interfacial shear strength Effect of fiber/matrix surface treatments on deformation behavior Identify the “affects” that leads to inconsistency Identify various defects and study their effects on deformation
behavior and mechanical properties Study the effect of these parameters on impact strength, hardness
and thermal properties Study the effect of process parameters on residual stress of the
composite Effect on mechanical behavior and failure mechanisms
Effect of process parameters and fiber matrix chemistry on cycle time reduction
Develop a micromechanical model to predict mechanical properties based on fiber distribution
Automotive requirements Reduction in cycle time Mass production Comparable mechanical properties Formability Apart from tensile properties, energy
absorption (crash worthiness), hardness and vibration charecterstics
What I am looking at? Initial work will be carried out at Deakin
where Fiber matrix combination will be identified Fabrication process will be finalized Initial property studies will be performed
@ NAL Facilities for property evaluation Fabrication facilities Assistance for micro mechanical modeling and
simulation Other assistance based on research progress
THANK
YOU
Experiment plan
Microsoft Office Word 97 - 2003 Document
References
Microsoft Office Word 97 - 2003 Document