考虑弯曲效应的混元胶接单搭接头应力模型

混元胶接接头是利用多种不同剪切弹性模量的胶层来传递被粘物载荷的单搭接头。它兼具胶层连续性连接和降低端头应力集中等优点，因此能充分利用被粘物材料性能(如复合材料)以提高接头强度。以典型双元胶接接头为对象，考虑加载作用线偏心引起的弯曲效应和胶层剥离正应力，建立被粘物为各向同性的线弹性双元胶接接头应力解析模型。理论模型中的胶层切应力、剥离正应力和上被粘物纵向正应力与精细有限元模型吻合得较好，证实了理论模型的正确性。参数研究中确定了影响混元胶层应力分布的关键耦合参数。

Theoretical Stress Model of Mixed-modulus Single-lap Adhesive Bonded Joints Considering the Bending Effect

Mixed-modulus single-lap joints are the bonded joints in which all of the load between two adherends is transferred within the variable modulus adhesive layer in the overlap region. The technique is demonstrated to combine the advantages of the continuous connection and of lowering the stress concentrations due to the variation of adhesive properties, which implies that a huge potential of bonded adherends such as composite materials and a substantial increase in joint strength could be realized. The theoretical stress model for symmetric bi-adhesive single-lap joints made of isotropic adherends is proposed on the basis of the linear elasticity mono-adhesive theory. The bending effect caused by the non-axial loading of the adherends and the adhesive peel stress, which is generally considered to be critical to joint failure, are taken into account in this investigation. The adhesive shear and peel stresses and upper adherend’s longitudinal normal stress in the analytical solution are obtained and compared with the numerical solutions determined by the two-dimensional linear elastic finite element analysis (FEA). The numerical experiment shows that the results of the theoretical and FEA models agree well. Finally, the relevant key parameters for the adhesive peak shear and peel stresses are identified and discussed.