Patent ID: 6952969
Filing Date: 2005-10-11
Classification: G01M,G01N

Abstract:
1. A method for determining the fracture toughness of a ball having an indentation defining an equator of the ball, the equator defining north and south poles of the ball, the indentation having precracks and a precrack length, the method comprising the steps of, applying an applied load in compression through opposing hemispherical surfaces having an arc length angle of less than ninety degrees, the opposing hemispherical surfaces conforming to the surfaces of the ball respectively at the north and south poles so that the ball bulges outwardly at the equator producing tensile stresses, load determining a critical applied load when the precrack begins to grow under the tensile stresses at the equator, and toughness determining the fractured toughness of the ball from the precrack length and the critical applied load.