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