Characterising the tensile strength of volcanic rocks at a broad range of strain rates

Korbinian Brauneis ¹\, Anthony Lamur¹, Jackie E. Kendrick¹

• Affiliations:  ¹Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität, Munich, Germany 

• Presentation type: Poster

• Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

• Poster Board Number: 127

• Programme No: 3.15.32

• Theme 3 > Session 15

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Abstract

* *K.Brauneis@campus.lmu.de * Mechanical failure is ubiquitous to any geological process in the Earth's crust and thus occurs at a wide range of deformation rates. Most studies looking at how rocks fail in tension are limited to a small strain rate range (e.g., 10^-5 10^-3 s^-1). Here we selected 3 rocks with varying porosities (ca., 2 -- 25%) from which we prepared 38x19 mm Brazil discs. We use a uniaxial press and a drop tower to characterise the tensile strength of volcanic rocks at strain rates from 10^-5 to 10³ s^-1. While the uniaxial press can bring the sample to failure at constant rates of 10^-5 -- 10⁰ s^-1, we estimate the strain rate in the drop tower by dropping an impactor, with an added mass ranging from 0 -- 30 kg, from different heights. We evaluate our results considering current empirical laws that aim at estimating the tensile strength of rocks as a function of porosity.