Amirkabir University of Technology Advances in Energy Sciences and Technologies 3115-9117 1 4 2026 04 01 Crack evolution on plasma-facing materials under the heat loads of tokamaks 340 348 6035 10.22060/aest.2026.25423.1003 EN Ali Masoudi Department of Physics and Energy Engineering, Amirkabir University of Technology, Tehran, Iran 0000-0001-5672-0734 Davoud Iraji Department of Physics and Energy Engineering, Amirkabir University of Technology, Tehran, Iran 0000-0003-2933-4904 Chapar Rasouli Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, Iran 0000-0001-7782-804X Journal Article 2026 01 10 Crack formation in plasma-facing materials (PFMs) under extreme transient heat loads poses a critical challenge for tokamak operation. This study investigates crack initiation and propagation in tungsten PFMs subjected to high transient heat fluxes using finite element simulations based on the Johnson–Cook constitutive model. Simulations were conducted for heat loads of 100 MJ/m² and 60 MJ/m² to capture the effects of both load amplitude and exposure time. At 100 MJ/m², cracks initiated at 0.15 s from the sample edges and propagated symmetrically toward the center, eventually leading to surface delamination. For 60 MJ/m², crack initiation was delayed to 0.5 s, with slower propagation and less extensive damage, demonstrating the strong dependence of crack evolution on both thermal load and duration. The analysis revealed that Mode I (opening mode) cracking predominates, driven by load gradients between surface and subsurface elements. These results provide quantitative insight into the thresholds for structural instability in tungsten PFMs and highlight the critical role of transient thermal stresses in predicting material performance under tokamak conditions. The findings offer valuable guidance for the design, selection, and engineering of PFMs in future fusion reactors. https://aest.aut.ac.ir/article_6035_4639475d6782a08c1e964f9a4329a254.pdf