A Novel Joint between Dissimilar Materials Inspired by the Mechanics of Trees

摘要

An integrated experimental and numerical investigation was conducted for removing the free-edge stress concentrations in dissimilar material joints. A convex interface/joint design, inspired by the shape and mechanics of trees, allows for least stress concentrations at bi-material corners for most engineering material combinations. In-situ photoelasticity experiments on convex polycarbonate-aluminum joints showed that the free-edge stress concentration was successfully removed. As a result, the new design not only improves the static load transfer capacity of dissimilar material joints, but also yields more reasonable interfacial tensile strength evaluation. For convex polycarbonate-aluminum and PMMA-aluminum joint specimens, the ultimate tensile load increased up to 81% while the total material volume reduced by at least 15% over that of traditional butt-joint specimens with severe free-edge stress concentrations.