Impact cratering experiments into quartzite, sandstone and tuff: The effects of projectile size and target properties on spallation

Poelchau, M. H.; Kenkmann, T.; Hoerth, T.; Schäfer, F.; Rudolf, Michael; Thoma, Klaus

doi:10.1016/j.icarus.2014.08.018

Cited by 35 publications

(52 citation statements)

References 36 publications

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“…Higher cratering efficiencies are reached for low-porous quartzites compared with the porous materials. Values taken from Poelchau et al [23] (Taunus quartzite) agree well with the cratering efficiencies for Wasa quartzite in the present study but lie slightly farther right because the porosity of Taunus quartzite ( ~ 1 %, [23]) is slightly lower than the porosity of Wasa quartzite ( ~ 3 %) used in the present study. This reduction in cratering efficiency for porous materials is attributed to energy dissipation caused by crushing of pore space.…”

Section: Resultssupporting

confidence: 88%

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Momentum Transfer in Hypervelocity Impact Experiments on Rock Targets

Hoerth

Schäfer

Hupfer

et al. 2015

Procedia Engineering

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A special phenomenon observed in hypervelocity impacts on rock targets is the so-called momentum multiplication, i.e. the momentum transferred to the target is greater than the original momentum of the projectile. This effect is caused by ejection of debris in the direction opposite to the flight direction of the projectile. In the present study momentum multiplication was investigated as a function of target material properties and projectile velocity. Hypervelocity impact experiments on target materials with different porosities were conducted and the momentum transfer was measured using a ballistic pendulum. Low porous materials like quartzite show larger momentum multiplication than porous materials like sandstone. The smallest momentum multiplication was measured for highly porous aerated concrete. Higher projectile velocity leads to higher momentum multiplication. Furthermore, this increase is stronger for low porous materials compared with porous materials. These observations can be explained by the different ejection behavior. Low porous materials show a directional and very fast ejection whereas porous materials show a slower ejection. The highly porous material shows a diffuse ejection behavior. Furthermore, cratering efficiency is reduced in porous targets leading to a smaller amount of ejected debris. This effect is attributed to energy dissipation caused by irreversible crushing of pore space.

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Section: Resultssupporting

confidence: 88%

“…In Figure 3 the cratering efficiencies are plotted as a function of the strength-term 3 (Equation (5)). For comparison, quartzite values from Poelchau et al [23] are also plotted. Higher cratering efficiencies are reached for low-porous quartzites compared with the porous materials.…”

Section: Resultsmentioning

confidence: 99%

Momentum Transfer in Hypervelocity Impact Experiments on Rock Targets

Hoerth

Schäfer

Hupfer

et al. 2015

Procedia Engineering

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“…Pi‐group plot for transient crater volumes for the MEMIN experiments with 2.5–12 mm projectiles (modified from Poelchau et al. ). On the ordinate π v (as the equivalent of mass displaced from the crater relative to projectile mass) times π 4 (the density ratio) was plotted together with π 3 (the ratio of the material strength to inertial forces) on the abscissa.…”

Section: Resultsmentioning

confidence: 99%

“…It has an age of 405 Ma and has experienced a low‐grade Variscan metamorphism (Poelchau et al. ), but the sedimentary layering is still apparent. Fractures are present on a decimeter scale and the quartzite has an average grain size of ~185 μm (Poelchau et al.…”

Section: Methodsmentioning

confidence: 99%

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Formation of shatter cones in MEMIN impact experiments

Wilk

Kenkmann

2016

Meteorit & Planetary Scien

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Shatter cones are the only macroscopic feature considered as evidence for shock metamorphism. Their presence is diagnostic for the discovery and verification of impact structures. The occurrence of shatter cones is heterogeneous throughout the crater record and their geometry can diverge from the typical cone shape. The precise formation mechanism of shatter cones is still not resolved. In this study, we aim at better constraining the boundary conditions of shatter cone formation in impact experiments and test a novel approach to qualitatively and quantitatively describe shatter cone geometries by white light interferometry. We recovered several ejected fragments from MEMIN cratering experiments that show slightly curved, striated surfaces and conical geometries with apices of 36°–52°. These fragments fulfilling the morphological criteria of shatter cones were found in experiments with 20–80 cm sized target cubes of sandstone, quartzite and limestone, but not in highly porous tuff. Targets were impacted by aluminum, steel, and iron meteorite projectiles at velocities of 4.6–7.8 km s−1. The projectile sizes ranged from 2.5–12 mm in diameter and produced experimental peak pressures of up to 86 GPa. In experiments with lower impact velocities shatter cones could not be found. A thorough morphometric analysis of the experimentally generated shatter cones was made with 3D white light interferometry scans at micrometer accuracy. SEM analysis of the surfaces of recovered fragments showed vesicular melt films alternating with smoothly polished surfaces. We hypothesize that the vesicular melt films predominantly form at strain releasing steps and suggest that shatter cones are probably mixed mode fractures.

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The effect of shock waves on diamagnetic fabrics

Tiwari

Agarwal

Kenkmann

et al. 2022

Preprint

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Para-and ferro-magnetic fabrics are known to provide essential clues for understanding impact cratering processes. However, research on the effects of shock waves on diamagnetic fabrics is lacking. We, therefore, conducted a hypervelocity impact experiment on a block of diamagnetic Taunus quartzite and studied the changes in diamagnetic fabrics. In the crater subsurface, the reorientation of the diamagnetic fabrics is concentrated in a zone of ˜4 projectile diameters (25 mm) width directly below the point of impact. Higher reorientation in this zone indicates the concentration of damage. We argue that although the shockwaves traversed through the target with a hemi spherical wavefront, the damage was concentrated directly below the point of impact.Another important observation is that the weak shock waves have changed the diamagnetic parameters. The bulk susceptibility has increased overall, while the corrected degree of anisotropy (P') and the shape parameter (T) have increased in the crater subsurface but have decreased at the target surface. We propose that the variable response of P' and T could be due to the difference in incident angle subtended by the shock wave on the diamagnetic foliation at the target surface (c. 34°) and in the subsurface (c. 54°). These results, thus, show that the changes in diamagnetic fabrics can be used as a proxy for plastic deformation caused by shock waves at low peak pressures.

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Impact cratering experiments into quartzite, sandstone and tuff: The effects of projectile size and target properties on spallation

Cited by 35 publications

References 36 publications

Momentum Transfer in Hypervelocity Impact Experiments on Rock Targets

Momentum Transfer in Hypervelocity Impact Experiments on Rock Targets

Formation of shatter cones in MEMIN impact experiments

The effect of shock waves on diamagnetic fabrics

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