About model formulation for longitudinal impact on compound bar with relation to investigation of safety for complex aircraft systems upon emergency conditions

Аuthors

Tishkov V. V.^*, Firsanov V. V.^**

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

*e-mail: tishkovvv@mai.ru
**e-mail: k906@mai.ru

Abstract

A technique is offered to find accelerations for elongated body at the moment of its longitudinal impact with perfectly rigid barrier for collision speeds up to 100 m/s. The body is modeled as a bar with geometrical and inertial properties varied stepwise along its length. It is assumed that stringback of the bar after initial impact is not taken into account; a deflection of waves is not considered during their passing through bar parts with different stiffness; the bar is made of isotopic metal material; internal contents of the body is reduced to some equivalent stiffness; sonic propagation speed along parts of the bsr is considered as a constant. Differential equations described oscillations of bar parts subject to appropriate initial and boundary conditions is solved using Laplace transformation as well as infinite series expansion for required displacements. A numerical example is given to demonstrate efficiency of the technique.