000904081 001__ 904081 000904081 005__ 20240711113822.0 000904081 0247_ $$2doi$$a10.1088/1741-4326/abe7bb 000904081 0247_ $$2ISSN$$a0029-5515 000904081 0247_ $$2ISSN$$a1741-4326 000904081 0247_ $$2Handle$$a2128/29833 000904081 0247_ $$2WOS$$aWOS:000637348300001 000904081 037__ $$aFZJ-2021-05651 000904081 082__ $$a620 000904081 1001_ $$00000-0003-1365-5930$$aVan den Kerkhof, S.$$b0 000904081 245__ $$aOptimized design of a tungsten–copper functionally graded material monoblock for minimal von Mises stress meeting the material operational temperature window 000904081 260__ $$aVienna$$bIAEA$$c2021 000904081 3367_ $$2DRIVER$$aarticle 000904081 3367_ $$2DataCite$$aOutput Types/Journal article 000904081 3367_ $$0PUB:(DE-HGF)16$$2PUB:(DE-HGF)$$aJournal Article$$bjournal$$mjournal$$s1648190804_11959 000904081 3367_ $$2BibTeX$$aARTICLE 000904081 3367_ $$2ORCID$$aJOURNAL_ARTICLE 000904081 3367_ $$00$$2EndNote$$aJournal Article 000904081 520__ $$aFunctionally graded materials (FGMs) are a means to remove discrete material interfaces which lead to high local stress concentrations, such as the tungsten–copper (W–Cu) interface of the current ITER monoblock design. This paper employs adjoint-based optimization methods to identify the highest potential reduction of stresses that could be reached with these materials, while ensuring that the local temperature does not exceed the material temperature operational window. The cheap sensitivity evaluation inherent to the adjoint approach enables the optimization of the detailed 3D material distribution. Furthermore, a novel optimization method based on an augmented Lagrangian formulation is proposed that allows accurate treatment of the material temperature window constraints. The temperature and stresses are modelled by the steady heat conduction and Navier's equation, respectively. We compare the results of different optimization formulations, with cost functions based on the von Mises stress and corresponding yield criterion and considering different values of the stress free temperature. To assess the performance under off-design conditions, two optimized designs were chosen and compared to the ITER and flat tile (FT) design, which consists of a copper block protected by a tungsten layer on top. The optimized designs lead to a factor 2–4 decrease in maximal stress near the original W–Cu interface of the FT design and a factor 10 decrease in yield criterion measure near the cooling duct. Under off-design conditions, they realized a factor 2–10 decrease in yield criterion in the upper part of the monoblock. This confirms numerically that FGMs can lead to significant design improvements. Finally, the inclusion of the material temperature operation window constraints leads to a decrease of 30–55 vol% W compared to the unconstrained cases, thus profoundly influencing the final design. The stress free temperature was found to have a comparably weaker influence on the final design with differences of 5–30 vol% W. 000904081 536__ $$0G:(DE-HGF)POF4-1232$$a1232 - Power-based Fuels and Chemicals (POF4-123)$$cPOF4-123$$fPOF IV$$x0 000904081 536__ $$0G:(DE-HGF)POF4-134$$a134 - Plasma-Wand-Wechselwirkung (POF4-134)$$cPOF4-134$$fPOF IV$$x1 000904081 588__ $$aDataset connected to CrossRef, Journals: juser.fz-juelich.de 000904081 7001_ $$0P:(DE-Juel1)156199$$aBlommaert, M.$$b1 000904081 7001_ $$0P:(DE-Juel1)2594$$aCoenen, J. 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