Influence of hygrothermal aging on the quasi-static and impact behavior of single lap joints using CFRP and aluminum substrates

Abstract

The use of adhesive to bond composites in vehicles continues to increase. Due to hygrothermal conditions, both adhesive and composite properties can be altered, making the mechanical behavior of a joint unpredictable. The novelty of this work is the assessment of the behavior of joints manufactured using composite and aluminum substrates tested under quasi-static and impact conditions in the following states: unaged, hygrothermally aged, and dried after hygrothermal aging. A significant reduction of failure load was registered for composite joints (quasi-static and impact) after hygrothermal aging. Joints dried after aging achieved a recovery in the failure load of quasi-static tests.

Keywords:

• CFRP
• aluminum
• quasi-static
• impact
• hygrothermal aging
• moisture
• joints

Acknowledgments

The authors gratefully acknowledge the funding provided by PhD grant SFRH/BD/139341/2018 “Impact strength optimization with cohesive zone elements of multi-material bonded structures used in the automotive industry”, Project N° 028473 POCI-01-0145-FEDER-028473 “Design methodology for impact resistant bonded multi-material automotive structures (ImpactBondDesign)”, Project NORTE-01-0145-FEDER-000022 – “SciTech - Science and Technology for Competitive and Sustainable Industries”, co-financed by Programa Operacional Regional do Norte (NORTE2020), through Fundo Europeu de Desenvolvimento Regional (FEDER). The authors would also like to thank NAGASE ChemteX^® for the financial support provided.