A comparison of the influence of nonlinear and linear creep on the behaviour of FRP-bonded metallic beams at warm temperatures. (1st February 2022)

• Record Type: Journal Article
• Authors: Wang, S.; Stratford, T.; Reynolds, T.P.S.
• Is Part Of: Composite structures. Volume 281(2022)
• Publication Date: 2022-02-01
• Subjects: FRP-strengthened structures -- Ambient-cured adhesive -- Nonlinear viscoelastic creep -- Differential thermal expansion; Composite construction -- Periodicals; Composites -- Périodiques; 624.18
• DOI: 10.1016/j.compstruct.2021.115117
• Languages: English
• ISSNs: 0263-8223

Abstract

Abstract: This study investigates whether it is necessary to consider nonlinear (rather than linear) adhesive viscoelasticity when considering the behaviour of an FRP-bonded metallic beam at warm service temperatures (25 °C, 30 °C and 40 °C). The paper presents finite element analyses that compare the effects of nonlinear and linear creep in the bonded joint for two different FRP-strengthened metallic beams (steel and cast-iron). This modelling work incorporates a viscoelastic adhesive constitutive model determined using a dynamic mechanical analyser for a commonly used ambient cure structural epoxy adhesive. The nonlinear viscoelastic behaviour of the strengthening adhesive was characterised using time-temperature superposition combined with the parallel rheological framework model. The study found that a model incorporating nonlinear viscoelastic creep only leads to a slightly larger joint slip (maximum 1.0% after 1 year) and a slightly lower CFRP axial stress (maximum 2.4% after 1 year), compared to an equivalent model using linear creep. This has a limited impact on the structural performance for the cases studied. In most cases, the simpler linear viscoelastic constitutive model is sufficient to analyse the behaviour of the FRP-bonded metallic beam in a warm environment.