Strength Measurement of Ceramic Spheres Using a Diametrally Compressed "C-Sphere" Specimen
- ORNL
- University of Wisconsin, Platteville
A "C-sphere" flexure strength specimen geometry was conceived and developed to measure the hoop tensile strength of bearing-grade silicon nitride (Si3N4) balls. Because such a strength can be measured, the important study of surface-located strength-limiting flaws in ceramic sphere is also enabled with this specimen. A slot is machined into the balls to a set depth to produce the C-sphere geometry. A simple, monotonically increasing uniaxial compressive force produces a hoop tensile stress at the C-sphere's outer surface that ultimately initiates fracture. The strength is determined using the combination of failure load, C-sphere geometry, and finite element analysis. Additionally, the stress field was used to determine C-sphere effective areas and effective volumes as a function of Weibull modulus. To demonstrate this new specimen, C-sphere flexure strength distributions were determined for three commercially available bearing-grade Si3N4 materials (NBD200, SN101C, and TSN-03NH), and differences among their characteristic strengths and Weibull moduli were found.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 930853
- Journal Information:
- Journal of the American Ceramic Society, Vol. 90, Issue 6; ISSN 0002-7820
- Country of Publication:
- United States
- Language:
- English
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