Differences in tensile and bending strength for knoop-cracked lead zirconate titanate specimens

The strength of piezoelectric ceramics differs greatly in tension and bendi ng tests. This effect, which is known to occur for specimens with a natural flaw population, also occurs in tests that involve Knoop-cracked specimens . In such samples, the linear-elastically computed bending strength is simi lar to 35% higher than the tensile strength. Computation of the actual stre ss distribution in the bending bars has shown that these differences are pr edominantly caused by the nonlinearity and nonsymmetry of the deformation b ehavior.