Alexander V. Gerasimov

Comparison of SPH and MLSM for Powder Particle Impact Modelling

In this article, SPH and MLSM methods are compared in application to particle impact modelling. It is shown, that both methods has important disadvantages because nonzero acceleration appears in the case of constant stress field with nonsymmetrical distribution of nodes in space. Some reasons of incorrect acceleration calculation are discussed.

First order accuracy conservative smooth particle method for elastic-plastic flows with contacts and free surfaces

A fully conservative first order accuracy smooth particle method is proposed for elastic-plastic flows. The paper also provides an algorithm for calculating free boundary conditions. A weak variational formulation is used to achieve energy and momentum conservation and to decrease an order of spatial derivatives for the boundary condition calculation, and the Taylor series expansion is used for restoring particle inconsistence and for getting at least the first order of accuracy of spatial derivatives. The approach proposed allows us to avoid the “ghost” particle usage.

NUMERICAL SIMULATION OF HIGH-VELOCITY INTERACTION ELEMENTS WITH THIN-WALLED STRUCTURES

The process of high-velocity collision of the elements of thin-walled structures with spherical and elongated projectiles, simulating fragments of cosmic bodies, artificial objects, ice particles and damaging elements is considered in three-dimensional Lagrangian formulation. The problem is solved taking into account probabilistic nature of crushing the material of the interacting bodies. Collision proceeds as normal and at an angle to a barrier surface. The approach proposed to solve fragmentation problems enables to reproduce the processes of barriers breaking with high-velocity elements in three-dimensional formulation which is the most complete from the physical point of view. The processes of interaction of the streams of high-velocity elements with thin-walled enclosures at different angles of approach to the latter, as well as the behavior of enclosure fragments and element debris behind the first shell of the construction, are of great practical interest to ensure reliable operation of spacecrafts, aircraft and missile technology. The streams of high-velocity elements may have different physical nature. They may be man-made and natural meteoric particles in space, ice particles in the atmosphere and damaging elements in all media. In this paper we consider processes of plates breaking by clusters of spherical and elongated projectiles and fragmentation pattern, as well as the formation of debris streams in behind-the barrier space.