Голубятников В.В.   Orlov M.Y.   Орлов Ю.Н.  

Numerical simulation penentrating functional graded materials

Reporter: Orlov M.Y.

It is known that the existing nomenclature of structural materials has long been inadequate for the growing demands of many industries. With the help of advanced technologies of powder metallurgy it became possible to create materials with a gradient of initial porosity, density and strength. The latter are objects of study of this work. Below we consider steel samples with a gradient change in the spall strength. In the samples there was a substrate with a special formulation composition.

Numerical studies of the process of impact of a thin plate and a steel barrier with a gradient substrate up to 300 m / s are carried out. The behavior of the material is described from the standpoint of the phenomenological macroscopic theory of continuum mechanics based on the fundamental conservation laws. The medium is elastic-plastic, compressible, porous, taking into account the strength properties, shock-wave phenomena and the joint formation of spall and shear fractures. Defining relations are given in the form of a Prandtl-Reis under the condition of Mises fluidity. The equation of state is chosen Walsh. As a numerical method, a modified Lagrangian method is used, the calculated part of which is supplemented by the mechanisms of splitting of the calculated nodes and the destruction of the calculated elements. A user-developed multifunctional software package for calculating modern dynamic multi-contact problems of mechanics of a deformable solid is developed. Such problems include the tasks of penetrating and deep penetration of impactors of complex geometry into structurally heterogeneous materials and structures.

The evolution of the destruction of homogeneous and gradient barriers, including the time of formation of the first foci of destruction, their propagation and localization is studied. Free-surface velocity profiles were constructed for each sample, the hydrostatic pressure at control points and the material damage parameter were calculated. During the counting process, the separation of the spallation plate from the main sample was recorded. The obtained data made it possible to determine the range of initial impact velocities at which the presence of a graded substrate increased the impact resistance of the sample.

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