The Mechanical Properties of Chelyabinsk LL5 Chondrite Under Compression and Tension

Abstract

The mechanical properties of Chelyabinsk LL5 chondrite (Chelyabinsk meteorite) were studied by uniaxial compression and diametral compression/indirect tension test. Twenty cylindrical samples, 10 for compression and 10 for tension, with the diameter 3.3 mm and 1.65 mm in height have been prepared for testing. It was shown that the strength of the tested samples under compression almost 45 times greater than it is at tension: 372 ± 10 MPa and 8.2 ± 0.7 MPa, respectively. Fracture behaviour under compression and tension was similar and can be characterised as brittle. The obtained compression strength of the Chelyabinsk meteorite lies close to the maximal values of strength for many other chondrites, whereas its tensile strength magnitude resides in the bottom quarter of the range of similar measurements. It may be caused by the small sizes of the investigated samples together with a large number of tiny cracks between the grains in the Chelyabinsk chondrite. Our estimations have shown that if one assumes that the initial shape of the Chelyabinsk fireball was spherical or ellipsoidal, then its fragmentation stress is close to the experimental tensile strength and much lower than the compression strength. Hence, a stress state equivalent to one appearing at the indirect tension test could occur in the Chelyabinsk fireball during its fall in the Earth atmosphere.