Two Experimental Methods to Measure the Damaged Subsurface of Carbon-Carbon Brake Discs

摘要

This paper deals with the measurement ofsubsurface damage of composite materials after braking situations.Several carbon-carbon composites materials have been studied andtested under industrial braking conditions. Two damagemeasurement methods were used to estimate the braking effects onthe mechanical behaviour of these materials. In particular, a meso-hardness test has been adapted to the heterogeneity of carbon-carbon composite and to their macro-porosity. Depending on thetype of material, the results show that meso-hardness is a goodindicator of local behaviour at a small depth under the surface. Forone C-C composite, reinforced with long random fibers, wemeasure the evolution of damage as a function of the distance ofthe braking surface. Another original compression-bending testwas also used, which confirms this damaged subsurface effect before wear occurs.