Optimized design of a tungsten–copper functionally graded material monoblock for minimal von Mises stress meeting the material operational temperature window

Abstract Functionally graded materials (FGMs) are a means to remove discrete material interfaces which lead high local stress concentrations, such as the tungsten–copper (W–Cu) interface of current ITER monoblock design. This paper employs adjoint-based optimization methods identify highest potential reduction stresses that could be reached with these materials, while ensuring temperature does not exceed operational window. The cheap sensitivity evaluation inherent adjoint approach enables detailed 3D distribution. Furthermore, novel method based on an augmented Lagrangian formulation is proposed allows accurate treatment window constraints. and modelled by steady heat conduction Navier’s equation, respectively. We compare results different formulations, cost functions von Mises corresponding yield criterion considering values free temperature. To assess performance under off-design conditions, two optimized designs were chosen compared flat tile (FT) design, consists copper block protected tungsten layer top. factor 2–4 decrease in maximal near original W–Cu FT design 10 measure cooling duct. Under they realized 2–10 upper part monoblock. confirms numerically FGMs can significant improvements. Finally, inclusion operation constraints leads 30–55 vol% W unconstrained cases, thus profoundly influencing final was found have comparably weaker influence differences 5–30 W.