Modelling wet lay-up CFRP–steel bond failures at extreme temperatures using stress-based approach

This paper focuses on predicting the triggering modes of failure and failure loads of CFRP–steel double-strap joints utilizing three different resins, two carbon fiber grades, and mild steel plates under extreme subzero and elevated-temperature environmental exposures encountered in civil infrastructure. Non-linear finite element models, at all currently investigated exposures, have been adopted. The results were compared with those obtained from previous experimental program. The double-strap CFRP–steel bond specimens of the experimental program were fabricated via the wet lay-up method. Therefore, a microstructural discretization approach was opted for the wet lay-up CFRP reinforcements, which incorporated the elasto-plastic behavior of the most vulnerable components, viz. resins, in the analyses. Uniaxial tensile properties of the adhesive material were utilized to describe the stress-based triggering failure mode for the joints. Limiting “maximum principal stress” and “Von Mises” yield criteria have been used for joints pre-conditioned below and above their adhesive/matrix's glass transition temperature (Tg). A third criterion was utilized to define “total interlaminar/localized interlaminar failure” patterns in both brittle and ductile material, viz. “transverse tensile stress” in the CFRP layer.