PSI - Issue 72

C.F.F. Gomes et al. / Procedia Structural Integrity 72 (2025) 34–42

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industry applications (Parashar and Mertiny 2012). Adhesive joining is also applied to join tubular components in the pipe manufacturing industry, such as in oil and energy production or wastewater treatment, in automotive chassis (aircraft, cars and buses), and even in space structures (Barbosa et al. 2018). The development of Finite Element Method (FEM) makes it possible to numerically predict the behavior of adhesive joints by simulating the geometry of the joint, the stresses involved and the plasticity of the adhesive and adherends. Cohesive Zone Models (CZM) combine the strength and toughness parameters of adhesives to accurately predict the joint performance (Khoramishad and Khakzad 2018). Strength prediction of tubular joints can be carried out using modelling software such as Abaqus ® or Ansys ® , which allows stresses and strains to be analyzed in the different loading phases, and application of advanced fracture criteria. The tubular joint can be modelled numerically in axisymmetric 2D models to analyze peel and shear stresses and predict failure under tensile or bending loads, or in 3D models if the joint is subjected to a torsional moment. The adhesive can be modelled with identical elements to obtain stress distributions or strength predictions using techniques such as continuum mechanics, fracture mechanics or Extended Finite Element Method (XFEM), or with cohesive elements in the case of CZM modelling. The topic of numerical prediction of tubular adhesive joints is addressed in the literature. Aimmanee et al. (2018) proposed a simplified analytical model to evaluate the tensile behavior of adhesive-bonded tubular strap joints. The tubes can have isotropic, orthotropic, or multilayer composite properties. Linear elastic adherends and adhesives, and axisymmetric conditions were enforced in the models. The obtained results provided design principles for these joints with different tube materials. The numerical work carried out by Rosas et al. (2021) using CZM studied the tensile performance of tubular overlap adhesive joints with aluminum adherends bonded with Araldite ® 2015. Different geometric parameters were studied (chamfers and fillets in the adhesive layer). The results of the joints with the addition of adhesive fillets at the overlap ends showed a significant reduction in shear stresses (60%), but this did not translate into an increase in joint strength due to plasticization of the adherends. The impact resistance of a tubular overlap joint with AW6082-T651 aluminum adherends bonded with the Araldite ® AV138 was studied by Silva et al. (2021) using a triangular CZM. Increasing the overlap length ( L O ) from 10 to 20 mm was shown to positively influence the joint’s strength by 43.7%. This trend also reflected on the joint’s energy dissipation at failure ( U ). Eusebio and Campilho (2019) evaluated the XFEM predictive capabilities for the strength of tubular overlap adhesive joints subjected to tensile loads, with different L O . The results showed an increase in stress concentrations with increasing L O . Smaller strength improvements with L O were observed for brittle adhesives compared to more ductile adhesives. The XFEM method showed worse predictions for highly ductile adhesives. The present work numerically compares the performance of three adherend materials in overlap tubular joints, considering the variation of the adherend material and L O . The developed numerical work enabled to obtain σ y and τ xy stresses in the adhesive layer using purely elastic models. Then, by CZM, strength prediction was carried out. 2. Materials and methods 2.1. Joint geometry The proposed technique, CZM, is initially validated by experimental test results. Thus, the overlap tubular joint geometry is initially introduced for both the validation study and numerical analysis that follows (Fig. 1). In this study, a single geometric parameter is varied, namely L O . This parameter has values of 20 and 40 mm for the validation study, and between 10 mm and 40 mm for the subsequent numerical analysis. Since the length of the adhesive joint remained the same, the adherends’ length ( L S ) varied depending on L O . The other parameters remained unchanged, and their designations and dimensions can be found in Table 1.