Wednesday, 13 October 2004 - 1:00 PM

This presentation is part of : Micromechanics and Physics of Materials

Modeling of Threshold Strength in Cylindrical Ceramic Structures

Glenn Beltz, University of California, University of California, Department of Mechanical Engineering, Santa Barbara, CA 93106-5070

Recently, three-dimensional structured ceramic composites with large threshold strengths (i.e., strengths below which there is zero probability of failure) have been fabricated utilizing a novel architecture consisting of relatively stress-free, elongated prismatic domains, separated by thin compressive walls. These structures are susceptible to fracture. Cracks, originating from large flaws within the elongated prisms, are arrested by the surrounding compressive layers until a specific stress level is attained (i.e., the threshold strength), thus resulting in a truncation of the strength distribution in the flaw region. A preliminary stress intensity solution has shown that this arrest is caused by a reduction of the crack driving force by the residual compression in the compressive walls. This solution also predicts that the threshold strength is dependent not only on the magnitude of the residual compression in the walls, but also on the dimensions of both phases. A simple analytic model, as well as a finite model, will be presented that utilizes a penny-shaped crack in the interior of such a structure or half-penny-shaped crack emanating from the edge of such a structure. Ongoing analytical and experimental work that is needed to more fully understand this arrest phenomenon and its application towards the development of reliable, damage-tolerant ceramic components will be discussed.

Back to Micromechanics and Physics of Materials
Back to SES Abstracts

Back to The 41st Annual SES Technical Meeting