Terminology of Materials

The class of Fiber Reinforced Polymers (FRP) can be separated into continuous (CoFRP) and discontinuous (DiCoFRP) fiber reinforced polymers. For the combination of CoFRP and DiCoFRP in one component, the abbreviation CoDiCoFRP is used.
Terminology

Fig. 1 Terminology of CoFRP, DiCoFRP and CoDiCoFRP

 

CoFRP

  • The arrangement of continuous fibers are approxiamtely homogeneous

DiCoFRP

  • The orientation distribution and the spatial arrangement of fibers show a significant degree of inhomogeneity and randomness
  • Fiber congregations and optional filler particles may be present
  • The strong spatial inhomogeneity is induced by the manufacturing process
     

Fiber Reinforced Thermoplastics and Thermosets

           

Fig. 2 Classification of fiber reinforced polymers based on average fiber length:

continuous fibers (left), long fibers (middle), short fibers (right)


Thermoplastics

  • Classification of the materials is usually introduced based on the average fiber length (Fig.2)
  • Separation between short fiber and long fiber reinforced composites (LFT) manufactured in compression molding is usually in the range of approximately 4 mm
     

Thermosets

  • Description is oriented on the manufacturing process of the compound
    - Bulk Molding Compounds (BMC)
    - Sheet Molding Compound (SMC)
  • No precise generally accepted separation concerning the used fiber lengths for SMC

Notation

  • Unified notation for all of the aforementioned composite types with respect to the fiber arrangement and the polymer system
    - Thermoset (TS)
    - Thermoplastic (TP)
  • Subdivided into
    - CoFRTS/DiCoFRTS/CoDiCoFRTS
    - CoFRTP/DiCoFRTP/CoDiCoFRTP

Abbreviations for different classes of composites

Fig. 3 Abbreviations for different classes of composites with specification of the polymer system
 

Combining the Advantages of Two Types of Reinforcements

Main advantages

  • DiCoFRP
    + Bulk material flow capability
    + Significant increase in the design freedom for components
    - Low load-bearing capacity
     
  • CoFRP
    + High load-bearing capacity
    - Restricted design freedom and formabililty

  • CoDiCoFRP
    + Optimal combination of design options
    + High stiffness and strength
     

         

Fig. 4 Demonstrator structure manufactured of DiCoFRP with local Co fiber reinforced patches

 

In contrast to CoFRP-like woven or non-crimp fabrics for which established design strategies exist, which are successfully used in Co-FRP engineering applications, the design strategies for CoDiCoFRP are to be developed in order to use CoDiCoFRP in structural applications.