A new test to determine the tensile strength of brittle balls-The notched ball test

Strength tests have been performed on commercial silicon nitride balls of 5 mm diameter. Two sets of specimens having notches of different length have been tested. Although the typical fracture loads in both sets of data are quite different, the tensile strengths are closely similar. This indicates the validity of the data evaluations. Experimental details are discussed and an analysis of the experimental uncertainties on the test results is made. For balls with 5 mm the uncertainties are estimated to be less than ±3% (of the measured value). For balls having a diameter of 10 mm or more the uncertainties are less than ±1%.