Page 81 - Research Report 2021 - Institut für Leichtbau und Kunststofftechnik

Dual-Doctorate: University of Bristol and TU Dresden
Dr.-Ing. Mario Valverde

An Improved Description of the Bonding and Consolidation
for Overmoulded Thermoplastic Composite Ribbed Plates

Supervising Professor: Professor Stephen Hallett (University of Bristol), Prof. Dr.-Ing. habil. Maik Gude (TU Dresden)

Thermoplastic composite overmoulding is an integrated deformations have been shown to affect the mechanical
process to manufacture components with combined con- performance, overall structural integrity, and component
tinuous and short fibre reinforcements. These compo- processability. This means that the modelling capabilities
nents benefit from high intrinsic mechanical properties, for predicting the mechanical performance at the over-
geometric complexity, and low production cycle times. moulded interface lack the required levels of complexity
The continuous fibre substructure is commonly designed to capture the response of the interface, in the absence
as the main load-carrying region, whereas the injection of bonding- and consolidation-influencing factors.
moulded substructure, typically serving as stiffening, im-
pact absorbing or functional features, can be tailored to The aim of this PhD thesis was to provide a refined de-
carry significant loads. Thus, ensuring a strong bond at scription of the bonding and consolidation phenomena
the overmoulded interface between the two substruc- at the overmoulded interface in CF/PPS (Carbon Fibre/
tures becomes a key objective. Polyphenylene Sulphide) and CF/PEEK (Carbon Fibre/Pol-
yetheretherketone) overmoulded ribbed plates. Through
Characterisation of the overmoulded interface has been manufacturing trials, process simulations and experimen-
a focal topic of research within the scientific community, tal testing, the mechanical performance was able to be
where models developed initially for non-isothermal ther- accurately predicted. The investigation of different part
moplastic bonding have been used to describe the av- designs and process parameters led to the identification
erage strength development across the interface area. of key structure-process-property relations and served
However, little to no work has been devoted to under- to develop a set of design and manufacturing guidelines
standing the variation of bond strength as well as the specific to overmoulding technologies.
preform insert consolidation, where process-induced

Diagrams of key stages during the over-
moulding cycle, showing final manufac-
tured CF/PPS ribbed plate.
© Dual doctorate: University of Bristol and ILK/TUD.

(a) (b) (c)

As-designed a), as-predicted (b), and
as-manufactured (c) overmoulded inter-
faces of a ribbed plate specimen.
© Dual doctorate: University of Bristol and ILK/TUD.

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