Higher order adhesive effects in composite beams

Composite adhesive bonded joints are widely used in various industrial and technological applications, including aerospace, electronics, biomedical, automotive, ship building and construction. In this paper, the attention is focused on layered structures consisting of two adherent beams bonded together by an adhesive layer. For such structures, a modeling approach based on the classical Timoshenko beam theory in conjunction with an adhesive model of imperfect interface is introduced. This imperfect interface approach, recently proposed by the authors in the contest of linear elastic adhesive and adherents materials, small strains and small displacements theory, models the asymptotic behavior of a thin interphase at higher orders for both the cases of hard and soft interface materials in a unified approach (Rizzoni et al., 2014). Accounting for higher order terms of the asymptotic expansions in the adhesive, the proposed approach generalizes simpler models based on the classical spring-type interface law or on the case of perfect contact between the adherent layers. The proposed methodology is used to evaluate stresses in two adhesive bonded joint configurations subjected to bending moment and transverse shear loading. Numerical simulations are produced and the results show good agreements with those obtained through finite element analysis.