材料因子と構造因子を考慮したマルチマテリアル接着構造体の共創設計

Abstract

In recent years, multi-material design has been applied in many industries. Among various methods of joining dissimilar materials, adhesive bonding has the advantage of being able to combine materials with dissimilar properties and relatively low weight. The strength of the adhesive structure is not only influenced by material properties but also structural factors such as thickness of adhesive layer. As a result, A co-design process including both material and structural factors is necessary. Experiments using pipe specimens with inclined surfaces bonded by epoxy adhesive were performed, whereby multiaxial stress states were realized simply by conducting a uniaxial tensile test. The failure function of the epoxy adhesive, expressed by the mean stress and octahedral shear stress, was then obtained from the experimental data and compared with that of acrylic adhesive previously reported in the literature reflecting material factors. The obtained failure functions of both adhesives were then applied to the shape optimization of the adhesive layer under different loading conditions. The optimization object is the strengthening of jointed structures reflecting structural factors. The optimal shape for different loading conditions differed for the different adhesives because of the driving force generated by the applied stress. The final shapes were thus optimized numerically to attain the highest mechanical integrity of the adhesive layer and found to be strongly dependent on the initial shapes before optimization.