PROGRESSIVE BENDING DEFORMATIONS OF FIRST WALL STRUCTURES UNDER CYCLIC THERMOMECHANICAL LOADING

Progressive deformations due to the combination of a cyclic nonlinear temperature distribution and electromechanical loadings may pose a ser ious problem for the design in advanced tokamacs. For first wall mock- ups exposed to a surface heat flux of 0.5 MW/m(2) and a load controlle d mechanical bending moment experimental and theoretical analysis was carried out under different cycle conditions. A simplified beam model was developed for the investigation of the thermomechanical behaviour. The special features of ratcheting under bending conditions are discu ssed.