Papers by Keyword: R-Line

Abstract: The paper presents a numerical technique to estimate the critical value of J integral, of a ductile metal (Aluminum alloy). Cracked, Single Edge Notch Bend (SENB) specimen of the alloy is modeled by finite element method. Load over the specimen is chosen such that the process or fracture zone is generated at the crack tip. The load is subsequently increased for the process zone size to go up. Process zone sizes and displacements under loads are measured from post processor solutions. Resistance curve and blunting line are plotted. Intersection of the two provides the value of. equals upon fulfillment of the plane strain condition. Various thickness values of the specimen are tried. The value of K_IC obtained from is found to be in close agreement with the reported value obtained from experiments.Nomenclature

Abstract: Fracture resistance of ceramics is evaluated by flaking off the specimen edge and chip scar surfaces are examined. The fracture resistance characteristic was calculated from the results of direct measurements that did not make use of linear fracture mechanics concepts, which is typical of conventional fracture toughness test methods. A fracture resistance test method termed the edge fracture (EF) method is discussed. This method is built upon measuring the flaking resistance FR on indentation of the specimen. The FR values for homogeneous elastic ceramics are proportional to the KIc ones determined by the SEVNB method. Flaking resistance vs chip size relationships (R-lines) are derived. Data analysis was built upon statistically reliable measurements on advanced alumina, zirconia, scandia, and silicon nitride ceramics.