A modified single edge V-notched beam method for evaluating surface fracture toughness of thermal barrier coatings

Abstract The surface fracture toughness is an important mechanical parameter for studying the failure behavior of air plasma sprayed (APS) thermal barrier coatings (TBCs). As APS TBCs are typical multilayer porous ceramic materials, direct applications traditional single edge notched beam (SENB) method that ignores those structural characters may cause errors. To measure more accurately, effects and on should be considered. In this paper, a modified V-notched (MSEVNB) with developed. According to finite element analysis (FEA), geometry factor structure recalculated. Owing narrower V-notches, accurate critical stress obtained. Based Griffith energy balance, reduction crack caused by micro-defects corrected. MSEVNB can accurately than SENB method.