Elastic Flexural Stresses in an Adhesively Bonded Functionally Graded Double Containment Cantilever Joint

This study investigates the 3D stress state of an adhesively bonded double containment cantilever joint with a functionally graded plate under a bending load. The mechanical properties of the through-thickness graded region between a ceramic (Al(2)O(3)) top layer and a metal (Ni) bottom layer were defined based on a power law distribution and modeled with a layered 3D finite element. The peak adhesive stresses occur around the support corners inside the adhesive fillets at the adhesive free edges. The von Mises stress increases uniformly from the plate half-thickness to both the ceramic and metal layers and becomes peak in the ceramic layer, and increases from the adhesive-metal interface to the adhesive-support interface through the adhesive thickness at the adhesive free edge. Both through-thickness adhesive and plate stress profiles and levels become similar after 20 layers. A ceramic-rich material composition results in similar smoother through-thickness stress profiles and reduces considerably differences between the peak stresses in the ceramic and metal layers. In addition, the Artificial Neural Networks combined with the finite element method indicated that the compositional gradient exponent, the support length, and the plate thickness affected considerably the elastic strain energy using whereas the adhesive thickness has minor effect. As the support length decreases the effect of the plate thickness becomes apparent and the support thickness becomes effective as the support length is kept constant. An optimal joint design requires a support length/plate thickness ratio of 25, a support thickness/plate thickness ratio of 3 and a compositional gradient exponent n between 2 and 10.