Semianalytic Weibull Model to Assess the Influence of Strength Controlling Flaws for Bimodular C-Ring Specimen

• Published in: Journal of testing and evaluation 2020-11, Vol.48 (6), p.4667-4698
• Main Authors: Bhushan, Awani, Panda, S. K.
• Format: Article
• Language: English
• ISSN: 0090-3973; 1945-7553
• DOI: 10.1520/JTE20170723

The present study addresses the issues of shifting of elastic axis and elastic surface for strength scaling of bimodular C-ring specimens using a Weibull statistical model. A semianalytical weakest link theory approach has been followed to evaluate the effective volume and effective area with presumed surface and volume distributed scattered flaws in the specimen. Experimentation, semianalytic, and finite element–based numerical procedures have been pursued to iteratively evaluate the Weibull characteristic parameters for typical loading configurations. Significant asymptotic variation in these two parameters has been observed at a low Weibull modulus for a set of change in elastic modulus ratio of tension and compression in contrast to unimodular assumptions. This variation can be ascribed to the significant shifting of neutral surface from the centroidal surface, thereby exhibiting the low level of confidence in designing bimodular structures. Also, the gradients of the curve are very steep, reflecting the uncertainty in strength characteristics as compared to the unimodular case, thus causing changes in the Weibull effective volume and effective surface area. The variation in Weibull effective surface area is less in comparison to the effective volume for unimodular and bimodular thick and thin C-ring specimens. The tabulated results can be used to substitute for a large number of expensive experiments for the design and analysis of bimodular structural components.