PSI - Issue 20

V.S. Kossov et al. / Procedia Structural Integrity 20 (2019) 212–217

213

V.S. Kossov et al. / Structural Integrity Procedia 00 (2019) 000–000

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1. Introduction

Operating experience shows that locomotives built in 1980–1990 are relatively easily damaged in case of the exhaustion of the draft gear travel or the automatic coupling destruction, when, bypassing the automatic coupling, the impact load falls directly on the front part of the body and the driver’s cabin, for example, during a collision of a locomotive at a railway crossing with a mobile vehicle (car, tractor, etc.) by Krasyukov (2014). Modern technologies of the computer simulation and the calculation of the stress-strain state of steel structures when subjected to an excessively intensive shock loading make it possible to predict the consequences of frontal collisions of locomotives (head cars) with an obstacle and to estimate their passive safety and resistance to damage with acceptable accuracy by Krasyukov et al. (2006). These technologies, in contrast to the full-scale experiments (crash tests) set up, turn out to be less expensive economically, allow to take into account many important behavioral features of the structure and its material under shock loading and make it possible to judge about the effectiveness of technical decisions made already in the early stages of the work with a project. As a result, the design period is reduced, its quality is improved.

Nomenclature W

absorbed energy

F max X max

ongitudinal impact force

impact protection wall displacement

M

matrix of inertia (mass) of the finite element model of the cab

D matrix of elastic-plastic behaviour of the model, the elements of which depend on the stress component σ and the displacement vector ū q vector of equivalent nodal loads caused by contact interaction of colliding bodies K c rigidity matrix G( σ ) geometrical rigidity matrix R( σ ) plastic rigidity matrix Δ u vector of nodal displacement increment Δ q vector of nodal load increment ε , σ relative elongation and stress σ p limit of proportionality σ e limit of elasticity σ y yield strength σ В tensile strength σ f fracture stress (conditional) ε В , ε f relative elongations at stresses σ В and σ f δ relative elongation after fracture ε  strain rate In the work presented in this paper, computer (virtual) finite element simulation and stress-strain state calculations of the locomotive load-bearing structures in an elastic and elastic-plastic set up using the MSC.Mentat/Marc and MSC.Patran/Dytran software systems were carried out. A collision of a locomotive with an obstacle was simulated as a transient dynamic process, the resolving equations were integrated by implicit and explicit methods. When assessing the effectiveness of the structural protection system of a driver’s cab under conditions of increased speeds of an accidental collision of a locomotive with an obstacle for more adequate simulation of the collision process and calculation of the stress-strain state of the body front part, additional factors such as the wave 2. Statement of the problem