Realistic material properties of porous agglomerates to model collisions between preplanetesimals
Final Report Abstract
An important but still not fully understood step in planet formation is the growth of cm-sized preplanetesimals to km-sized planetesimals. Whether a collision of two preplanetesimals leads to sticking or to destructive fragmentation depends crucially on the material properties of the preplanetesimals. Observations as well as theoretical models indicate that preplanetesimals are not solid rocks but consist of highly porous agglomerates. Therefore, it is important to apply a realistic porosity model if the outcome of collisions between preplanetesimals should be determined by computer simulations. In this project, we have developed such porosity models. Because we could prove that modern approaches like the ε - α porosity model show non-physical behaviour for materials with intermediate and high porosities, we developed a general an exhaustive classification system which enabled us to create and test arbitrary porosity models that are based on properties of the matrix material of the porous object. In addition, we generalised simple porosity models that are based on plastic deformations of the object. In particular, we included previously neglected effects like thermal effects and damage due to tension, and we considered the additional internal energy of those porous objects due to the surface energy of the pores.
Publications
- 2010, "Pore surface energy corrected P-alpha like models and the anomalous behaviour of porous materials". International Symposium: "Plasmas in the laboratory and in the universe: interactions, patterns, and turbulence", 1-4 December 2009, Como, Italy, AIP
Arena, S.E., Speith, R.
