Tensile & shear strength of porous dust agglomerates

Abstract

Context.Within the sequential accretion scenario of planet formation, planets are build up through a sequence sticking collisions. The outcome of collisions between porous dust aggregates is very important for the growth from very small dust particles to planetesimals. In this work we determine the necessary material properties of dust aggregates as a function the porosity. Aims: Continuum models such as SPH that are capable of simulating collisions of macroscopic dust aggregates require a set of material parameters. Some of them such as the tensile and shear strength are difficult to obtain from laboratory experiments. The aim of this work is to determine these parameters from ab-initio molecular dynamics simulations. Methods: We simulate the behavior of porous dust aggregates using a detailed micro-physical model of the interaction of spherical grains that includes adhesion forces, rolling, twisting, and sliding. Using different methods of preparing the samples we study the strength behavior of our samples with varying porosity and coordination number of the material. Results: For the tensile strength, we can reproduce data from laboratory experiments very well. For the shear strength, there are no experimental data available. The results from our simulations differ significantly from previous theoretical models, which indicates that the latter might not be sufficient to describe porous dust aggregates. Conclusions: We have provided functional behavior of tensile and shear strength of porous dust aggregates as a function of the porosity that can be directly applied in continuum simulations of these objects in planet formation scenarios.

Accepted for publication in A&A

References in corpus (5)

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• The Physics of Protoplanetesimal Dust Agglomerates. IV. Towards a Dynamical Collision Model
• Collisions between equal sized ice grain agglomerates
• Compression Behaviour of Porous Dust Agglomerates
• Numerical determination of the material properties of porous dust cakes

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• Thermal inertias of pebble-pile comet 67P/Churyumov-Gerasimenko
• Rotational Disruption of Porous Dust Aggregates due to Gas Flow in Protoplanetary Disks
• Synthetic Modelling of Polarized Dust Emission in Intermediate-Mass YSOs: I: Constraining the Role of Iron Inclusions and Inelastic Relaxation on Grain Alignment with ALMA Polarization
• The rotational disruption of porous dust aggregates from ab-initio kinematic calculations
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• Gas permeability and mechanical properties of dust grain aggregates at hyper- and zero-gravity