ROLLING STOCK ENGINEERING CENTRE

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011

ROLLING STOCK ENGINEERING CENTRE

Centre d’Ingénierie du Matériel

4 allée des Gémeaux 72100 Le Mans

DIRECTION DU MATÉRIEL


Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011

Centre d’Ingénierie du Matériel

4 allée des Gémeaux 72100 Le Mans

N°2 Document propriété de la SNCF - Reproduction interdite

STUDY ON ENGINE MOUNTING


Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011



REPORT AND MODIFICATION OF THE RESILIENT MOUNTS

Report and collision analysis concerning freight locomotive

SNCF STUDY ON THE ENGINE MOUNTING ELEMENTS

Analysis of the mounting elements and new proposal

Calibration of the plastic deformations on the initial mounting and application to the new elements

Additional study

CONCLUSION

INTRODUCTION

Tightening effect on the behaviour of the mounting elements

Study on the origin of the plastic deformations


Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011



INTRODUCTION

Since close to 20 years dedicated to the dynamic calculations

and the associated railway structures design, one of the

recurrent questions is concerning the link between a dynamic

load according to the time and its quasi-static equivalence.

For the pre-design of the train, the main basic hypothesis is that the

dynamic resistance of the carbody structure of the trains is from 1,5

to 2 times the static design load

at the corresponding level.

2000 kN

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011

DIRECTION DU MATÉRIEL N°5 Document propriété de la SNCF - Reproduction interdite


INTRODUCTION

A recent example of problem linked to the static design of

systems functioning under dynamic conditions corresponds to

the engine mounts behaviour of the locomotives during a

rough shunting.

Indeed, the direct use of the formula F = m. with a dynamic

coefficient limited to +20%, considering the engine mass as

rigid and the standardized deceleration limit, doesn't permit

to obtain the real behaviour of the supports and can lead to

the deformation of these elements.

BB 66060 BB 475049

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011




22 km/h

Report and analysis of a freight locomotive collision

During the collision between a new crashworthy locomotive (BB475049) and two locomotives (BB66060 and BB427057), with a speed of 22 km/h, 5 on 6 resilient mounting elements have moved (distorsion with rotation of 5-10°).

No other element or fixings were modified.

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011





A SNCF (CIM) analysis identified the process of the old crashworthy device of the locomotive BB66060, with the absorbed energy and the corresponding crushing force.

The behaviour of the different crashworthy devices is fitted. Then, the rolling stocks were efficiently protected during the collision.

The mean longitudinal deceleration level is approximately of 2g. It should protect the equipment and theirs fixings, designed with 3g (according to the europeean standard EN12663)

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011





Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011





For the deceleration less than 3g : the engine mounting are subjected to plastic strains.

For the deceleration less than 1g : the engine mounting are subjected to sliding.

ANALYSIS

For the material characteristics : in accordance with the specifications.

For both alternator and engine : no failure and no distorsion.

Distorsion of the

adjustment screw

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011




The adjustment screw is extended and its material characteristics improved (same external sizes and interfaces).


Evaluation under 3g and 5g by tests and numerical FE simulations. The forces are of 75 kN for 3g and of 125 kN for 5g (including 15 % for safety margin).

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011




No calibration of the numerical model (original version) according to the deformations encountered during the collision (only static simulations and theoretical extrapolation).


The Calibration must be carried out in order to :

Validate the method with the application of the force in the

lower part of the resilient mounts.

Identify the force level associated with the upper deformation

of the central element (6 mm).

Verify that the modification is sufficient for this force level.

Study the influence of the tightening and the maintaining with

deceleration.

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011



Calibration of the plastic deformations on the initial

mounting and application to the new elements

Quasi-static numerical simulation with Radioss (sufficient duration to limit the dynamic effects and rigid bodies to ensure a complete tightening).


Successive calculations from 75 kN to 150 kN to determine the residual deformation of 6 mm.

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011





The calibration shows that the initial engine mounting is deformed with a force from 140 to 150 kN, corresponding to a mean deceleration from 5,5 to 6,5 g (with the safety margin of 15% resulting from dynamic effects).


Application on the new reinforced element to validate the modification.

Good location of the deformation

(135 mm from the lower part) and

support on the upper part of the

rubber surface.

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011






Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011





The improvement of the resilient mounts is acceptable under the collision forces obtained with the calibration.


Comparison of the two versions with 150 kN, at the end of the calculation

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011






Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011



Additional study : tightening effect on the behaviour of the mounting elements

Complete release of the tightening (the friction of 0,15 is applied on the different interfaces for the contact without pre-stress).


For the loading of 150 kN, the location of the central screw deformation is different from the valuation (level of 150 mm instead of 135 mm, and more severe).

During the collision, the element mounts had to be tighten.

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011






For the reinforced version, the deformation can occur if the tightening is not ensured.

Necessary determination of the minimum tightening torque to maintain the assembly during the collision.

Comparison of

the deformations

in the two

versions

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011






Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011




The tightening force is applied with a spring between the lower side of the nut and the upper side of the adjustment screw (with a force of 140 kN for 580 N.m).


No problem with 140 kN in the numerical simulation.

Problem under 50 kN representing a sufficient safety margin.

Force of

50 kN

Force of

35 kN

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011



Additional study : study on the origin of the plastic deformations

Numerical simulation to understand why a deceleration smaller than 3g can generate forces corresponding to 6.5g, distributed on the 6 resilient mounts (140 kN to 150 kN).


Modification of the material characteristics of the resilient mounts

No significant influence of the rubber-steel stiffness or the material characteristics decrease on the deformation

Simulation with the effective deceleration on the engine-alternator


Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011




Numerical simulation to understand why a deceleration smaller than 3g can generate forces corresponding to 6.5g, distributed on the 6 resilient mounts (140 kN to 150 kN).



The results confirm the hypothesis of the dynamic increase on the equivalent quasi-static force of 15% (from 10 to 16% according to the deceleration level).

For the elements deformation, two behaviour are highlighted :

A uniform behaviour of the elements when they are not subjected to permanent deformation.

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011






For the elements deformation, two behaviour are highlighted :

A non uniform behaviour of the elements when they are subjected to permanent deformation.

The results validate the equivalent method with the application of the force in the lower part of the resilient mounts.

The results cannot explain the level of deformation for a deceleration smaller than 3g.

Patrick JUMIN

5th European HTC

Bonn, Nov 9th 2011


CONCLUSION

This study permitted to verify that the modification of the resilient mounts is sufficient for the force level occurring during a rough shunting, if a sufficient tightening is applied.


The hypothesis of the the equivalent quasi-static force increase of 15% (dynamic effects) was validated, as the uniform behaviour without plastic deformation.

This study has not explained the levels of both force and deformation for the limited mean deceleration. This lack of understanding represent a risk for the future engine mounting development in railway industry (necessary added study on the real behaviour).

Business

ROLLING STOCK ENGINEERING CENTRE