# Numerical modelling results of the products structures upon the impact when hitting liquid and solid impediments

### Аuthors

Yudin D. A.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: mailto:clasic29.00@mail.ru

### Abstract

The article presents an adaptive theory and the results of mathematical modeling of structural elements of products while encountering with various types of obstacles. The problem of developing an effective method for the numerical simulation of three-dimensional dynamic problems of hydroelasticity and structural dynamics is being solved. Finite element method is used to solve these coupled problems.

The results of the stress-strain state calculations using numerical simulation, as well as some highlights of the process of impact interaction of the product and obstacles are obtained.

In recent years, a large number of analytical and semi-empirical methods have been developed to study the stress-strain state of structures under impact. However, these methods were used mainly for a limited type of structures, as a rule, of simple geometry and in the presence of a number of restrictions in the problems formulation and boundary conditions formation. At the same time, it is obvious that in order to solve practical problems along with those of the objects of the rocket and space industry, it is necessary to account for rather complex geometry of structural elements and the corresponding boundary conditions. The main modeling problem in this case is the need to obtain a joint coordinated solution of the equations of structural dynamics and the equations of flow of liquid or solid barrier. In this regard, numerical modeling is considered to be one of the main and non-alternative approaches these days for solving these complex problems.

The advantages of the FEM are as follows: relatively simple setting of boundary conditions, sufficiently high accuracy, and the capability of tracing the entire evolution of the free boundary as well as a high degree of universality. It is worth noting that this method application while performing calculations in the areas with complex free surface behavior can lead to the cell grid boundaries overlapping due to large deformations of the simulated structure.

The goal of the work consists in developing an effective methodology for numerical modeling of three-dimensional dynamic problems of hydroelasticity for specifying the stress-strain state of elements of metal structures impact upon water and a solid impediment impact.

### Keywords:

stress and strain, ricochet burst, failure, approach velocity, entry angle, membrane destruction, damper crushing

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