Tuesday  |  Phipps  |  01:40 PM–02:00 PM

#13370, A Novel Rotating Flexure-Test Method for Brittle Materials

The failure of brittle materials is governed by the growth of microstructural flaws. These flaws, being randomly distributed, can lead to orientation-dependance of the measured flexural strength. In a four-point bending test, if the point under maximum tension contains the critical flaw in the sample, the measured flexural strength will be its true value. However, if the specimen is rotated to any other orientation, this critical flaw will be under a lower tensile or a compressive state of stress, resulting in a higher measurement of flexural strength. Our goal is to measure the true flexural strength of the specimen by ensuring that failure occurs at its weakest point. This can be achieved by loading a solid or hollow cylindrical specimen as it rotates along its longitudinal axis, thereby activating its critical flaw during a four-point bending test. This allows every point on the specimen’s surface to experience a state of maximum tension at any given load. Using a novel test fixture, we have measured the true flexural strength of a variety of cylindrical brittle and semi-brittle materials and compared our results to existing experimental data obtained through traditional four-point bend tests. While conducting experiments we reproduced data trends found in literature, further validating our test fixture.

Michael MacIsaac   University of Florida
Salil Bavdekar   University of Florida
James Nance   University of Florida
Nam-ho Kim   University of Florida
Bhavani Sankar   University of Florida
Ghatu Subhash   University of Florida