A SIMPLE METHOD FOR CALCULATION OF RESIDUAL STRESS IN THERMAL BARRIER COATING

The residual stresses are always emerged in plasma sprayed coatings due to their spray method.The accurate calculation of the residual stresses is important for strength evaluation and thermal fatigue prediction of the coatings,as well as for controlling and evaluating the spraying process.First of all,a main process causing residual stress is identified by analyzing plasma spray process and simplified into a model.The residual stresses in the coated part is resulted from the difference in thermal expansivities of the various materials involved.According to the above mentioned,authors bring forward a simple method for calculating residual stresses,which can be easily used with finite element method.Finally,as a demonstration,cylinder-type specimens are chosen to calculate residual stresses with FEM under various calculating conditions.