50 Years of Characterizing Structural Ceramics and Glasses: Recognizing the Contributions of George Quinn: Mechanical Testing & Design/Fractography & Failure Analysis
Sponsored by: ACerS
Program Organizers: Jeffrey Swab, Army Research Laboratory; Andrew Wereszczak, Oak Ridge National Laboratory
Wednesday 2:30 PM
October 12, 2022
Room: 404
Location: David L. Lawrence Convention Center
Funding support provided by: Corning Inc., 3M, Orton, and Bomas
Session Chair: Andrew Wereszczak, Oak Ridge National Laboratory; James Varner, Alfred University
2:30 PM Invited
Interpretation of ZerodurŪ Strength Data
: Jonathan Salem1; 1NASA GRC
The strength distribution of of ZerodurŪ, as machined and etched, is investigated and determined to be best represented by a normal distribution with large variance but without scale effects. The appearance of a 3-parameter Weibull distribution results from mixing of components of variation. Although a 3-parameter Weibull distribution might be reasonably used, the size effect is missing, and the fixity of the threshold is questionable. Thus, a classical design approach might be used for structural design with this flaw population.
3:00 PM Invited
Fractal Analysis of Brittle Fracture and Crack Branching: John Mecholsky1; Daniel DeLellis1; Nicholas Mecholsky2; 1University of Florida; 2Catholic University of America
Fracture surfaces of materials that fail in a brittle manner have been shown to be fractal. Crack branching patterns have also shown to be fractal. However, the two conditions are not the same. The fractal dimension of the fracture surface is independent of the strength and dependent on the fracture toughness. The crack branching pattern is a function of the strength. I will demonstrate that there is a relationship between the two situations of fractal character. George Quinn has been involved with identifying the crack branching patterns along with clarifying crack branching angles in the literature. I will show his contribution to understanding of the difference between fracture surface fractal dimension and the fractal character of crack branching.
3:30 PM Break
3:50 PM Invited
Coating Effect on Vial Crack Response: Jamie Morley1; Alicia Gallagher1; James Webb1; Steven DeMartino1; 1Corning Incorporated
Sterility compromising cracks in pharmaceutical glass containers are a consistent source of concern for the pharmaceutical industry. This presentation analyzes the effect and fractography of applying low coefficient of friction coating on the generation of bruise, a.k.a. bump check style damage on borosilicate vials. Damage was simulated at multiple loads in a lab setting allowing a comparison of damage on coated and uncoated vials. The results show that coating reduces the severity of surface damage and the rate of through crack generation, resulting in vials that are more robust to known damage sources.
4:20 PM Invited
Failure Analysis of a Large SiC Component: Kristin Breder1; Eric Buchovecky1; Ryan Koseski1; 1Saint-Gobain
A large silicon carbide part was being inserted into a specific application assembly at a customer using heat shrinking. Sounds consistent with fracture were reported by the installing engineers within 20-30 seconds of inserting the part into a heated metal sleeve. Based on fractographic analysis and finite element modeling, it is clear that the component failed due to the thermal gradient induced across the component in the process. The fracture origin was likely a grinding flaw, but surface features near the fracture origin were inside the specified tolerances. There did not appear to be any physical feature (e.g. inclusion, pore, micro-crack) or chemical inconsistency near the origin. Measurement of the mirror constant indicated a failure stress consistent with the stress level seen in the model. The customer was recommended to change the process conditions to account for the larger part to significantly reduce the thermal stresses during the process.
4:50 PM Invited
On the 3rd Edition of the NIST Guide to Fractography of Ceramics and Glasses: George Quinn1; 1NIST
Fractography is a powerful but underutilized tool for the analysis of fractured glasses and ceramics. The 1st edition of the NIST Guide was published in 2007. Its goal was to make fractographic analysis of brittle materials less an art and more an engineering practice for scientists and engineers. The 3rd edition of 2020 added new developments in our field, new equipment and techniques, and some new case studies. It expanded some topics that were glossed over (e.g., terminal crack velocities, thermal shock) in the earlier editions. The 3rd edition has 16% more content than the 2nd edition, and now there are over 1130 figures. Judicious layout adjustments were made so that the physical size of this book was only 3% larger than the 2nd edition of 2016. This presentation discusses how the Guide has evolved. A 4th edition is possible in the future.