Design and testing of surface modifications for hybrid composite-metal joints for Formula One car application

The increasing demand for lightweight, high-performance structures in advanced engineering applications has driven the development of multi-material assemblies that combine metals and composite materials. This thesis investigates adhesive bonding as a joining methodology for hybrid composite-metal joints, addressing the challenges of creating reliable, load-bearing connections between dissimilar materials. The primary objective of this research is to evaluate the mechanical performance and failure behavior of adhesively bonded composite-titanium joints under tensile loading, comparing different adherent designs and manufacturing processes for both primary and secondary bonding approaches. Experimental specimens consisting of carbon fiber reinforced polymer (CFRP) composite adherents bonded to titanium metal adherents were manufactured and tested. A total of 26 different joints were evaluated. The titanium adherents were manufactured using both conventional subtractive machining and additive manufacturing processes to evaluate the influence of different production methods on joint performance. Two bonding methodologies were implemented: secondary bonding, where adherents were fully manufactured before joining, and co-bonding, where the composite was cured simultaneously with the metal components to ensure structural integration. Tensile testing was performed on all specimens using servo-hydraulic testing equipment. Failure modes were classified according to ASTM standards, distinguishing between fiber tear failures in the composite, adhesive failures at layer interfaces, and mixed failure mechanisms. Results demonstrated that joint performance was strongly influenced by the adherent geometry and manufacturing history of the metal components. The research establishes baseline mechanical properties and failure behavior data for composite-metal adhesive joints, providing insights into design optimization and manufacturing control requirements for reliable multi-material assemblies in performance-critical applications.