Abstract
The equations for the evaluation of fracture toughness by chevron notched beam, with using the bending bar whose shape is followed as JIS-R1601, are obtained analytically for five different shapes of the notch, with the method by Munz. The accuracy of the equations is tested experimentally with alumina specimens. Except one condition (stand-up type, θ=120°, α0>0.6), scattering of the average value obtained from the experiment with every equation is within ±8%, and this scattering is almost same as the relative standard deviation of the fracture toughness of the tested alumina itself, ±7%. Then, these equations are useful if we want to evaluate fracture toughness with about this accuracy, even if the specimen is used as either stand-up or lay-down type.
