top of page

FISITA Library

EB2021-FBR-009

Video + Slides

Abstract

Dr. Hoang Long Le Tran, École Centrale de Lille, FRANCE

Dr. Anne-Lise Cristol, École Centrale de Lille, FRANCE

Dr. Vincent Magnier, Ecole Polytech Lille, FRANCE

Dr. Jérôme Hosdez, University Lille, FRANCE


Sintered metallic composite is widely used as brake pad material for high energy railway thanks for its good resistance to severe solicitations caused by braking loads. Despite its efficiency, the degradation of the material properties under the effect of brake loads has been noticed in literature which is undoubtedly induced by the microstructure evolution. However, the microstructure evolution and its relation with mechanical behavior have so far not been intensively investigated due to the complexity of braking solicitations.

To solve the problem without tackling it in all its complexity, two experimental tests were proposed where physics are decoupled; but still inspired by the braking sequence in terms of applied temperature and compressive load. The first one is the thermal solicitation test where a temperature gradient from 400°C to 540°C was applied to the material. The second one is the thermomechanical test where a compressive load at 20 MPa was applied under the same thermal gradient. The experiment time is fixed for two minutes, equivalent to the time of one braking stroke. Besides, the local microstructure evolution of the sintered metallic brake pad was characterized by Electron Microscopy (SEM) coupling with Energy-dispersive X-ray Spectroscopy (EDS) and X-ray microtomography. The evolution of mechanical properties was characterized by a series of compressive tests equipped with a Digital Image Correlation (DIC) for analyzing deformation behavior.

Based on the deformation behavior characteristics, the considered thermal and mechanical solicitations have no separate effect on the mechanical properties of the material. The sole evolution of mechanical behavior is due to the coupled thermomechanical solicitation, which increases the hardness of friction material. From the strain field analysis, the evolution takes place on the strain lines determined by the compressive test, which strongly depends on the distribution of graphite inclusions in the microstructure. The change in mechanical behavior is induced by the local microstructure evolution. Indeed, thermomechanical stresses cause the densification of the graphite in the normal direction, this structural change induce some shear cracks in the basal plane. In terms of the metallic matrix, the segregation of carbon in steel is investigated as a reason for the increased stiffness.

EuroBrake 2021

FOF

WATCH VIDEO
DOWNLOAD PDF
DOWNLOAD SLIDES

Downloads

LOAD MORE

Error message goes here.

SEARCH

Person profile goes here.

France

Associate Professor

Company Text

Job title

Company Name

Company Text

Dr. Anne-Lise Cristol

FISITA Committees & Groups

Executive Board

News on FISITA Spotlight

16 July 2021

Spotlight title

Stay up to date with FISITA Spotlight

More Blogs Item Title

Excerpt from the blog goes here - this will give the reader a brief snapshot of what the post is about...

16 July 2021

READ NOW
bottom of page