Car engine F-1 Mass ratio Volume ratio Power, kWt

Brake system of F-1 car

Acceleration dynamics Braking dynamics

Investigation directions prediction of thermal load on the friction contact elaboration of physico-chemical principles of optimizing structure and properties of matrix polymer use of ecologically safe reinforcing fibrous components improvement of efficiency reliability and comfort of frictional interaction (braking) lowering vibroacoustic activity of friction devices optimization of design of friction parts by strength and reliability criteria provision of quality of materials and products during production monitoring of materials and tribosystems economics of tribosystems

Investigation directions prediction of thermal load on the friction contact elaboration of physico-chemical principles of optimizing structure and properties of matrix polymer use of ecologically safe reinforcing fibrous components improvement of efficiency reliability and comfort of frictional interaction (braking) lowering vibroacoustic activity of friction devices optimization of design of friction parts by strength and reliability criteria provision of quality of materials and products during production monitoring of materials and tribosystems economics of tribosystems

SEM photomicrographs of the fibrous filler original basalt fibers basalt fibers treated with adhesive

Morphological analysis of debris Original components Filler particle distribution by size Adhesive wear Plasticized material debris distribution by size Abrasive wear Distribution of debris by size of plasticized material with fillers preliminary treated by adhesives

Porous structure of the frictional material   The mainline crack position at uniaxial tension Dependence of damageability on tensile (a) and compressive (b) stresses Pores on the friction surface

Nucleation and propagation mechanisms of microcracks in frictional composites   Dependence of microdamageability on loading at uniaxial tension Microcrack on the friction surface

Computing scheme of frictional joints and machine parts by the finite element method     Creation of virtual model for a real object Optimization of design, technology and material: corrective action Experimental data (bench test and other) Conclusions Creation of finite-element model   Solution: computation of temperature, stress and strain Analysis of computation results and their comparison with experimental data

Design optimization of friction metal-polymer ware a  b basic and optimized designs of the metal backing of braking disk c  d Mises distribution of equivalent stresses over outer contact and inner surface of the friction lining conjugated with the metal backing for the basic and optimized designs

Asbestos-free frictional materials   Technical characteristics of frictional materials Production structure

A frictional contact model for a disk brake Brake disk Heat models of the frictional contact

Results of solving the problem of a thermal contact at nonstationary friction and movable contact interface Braking time t=0.1 s sz min = -10.8 MPa sz max = 8.8 MPa p, MPa         Distribution of contact pressures across the frictional lining width at different braking time Braking time t=0.5 s sz min = -14.2 MPa sz max = 32.2 MPa Braking time t=2.0 s sz min = -33.8 MPa sz max = 16.9 MPa T, °C           Temperature distribution across the frictional lining width at different braking time Braking time t=tB=3.5 s sz min = -19.7 MPa sz max = 6.9 MPa

Temperature dependence on the frictional lining surface upon number of brakings heat model 1 Cyclogram of disk brake loading braking time tB = 3,5 s cooling time of rubbing surface t2-tB a single cycle duration t2= 270 s heat model 2 1 - at the end of each braking cycle 2 - at the beginning of each following braking cycle h - counterbody thickness

Temperature dependence on the counterbofy surface upon number of brakings heat model 1 Cyclogram of disk brake loading braking time tB = 3,5 s cooling time of rubbing surface t2-tB a single cycle duration t2= 270 s heat model 2 1 - at the end of each braking cycle 2 - at the beginning of each following braking cycle h - counterbody thickness

Temperature distribution across friction pair thickness in metal counterbody Cyclogram of disk brake loading braking time tB = 3,5 s cooling time of rubbing surface t2-tB a single cycle duration t2= 270 s number of braking cycles - 10 h - counterbody thickness

A set of technical facilities for technological diagnostics of frictional materials 1 – Hydraulic press 2 – pellet mold 3 – plane-parallel plates 4, 5, 15 – displacement and force grauges 6, 7, 8 – temperature gauges 9, 10, 11 – control units 12, 13, 14 – recording instruments

Determined technological parameters of frictional materials r – material density P – minimal pressing pressure 1.70 - 2.25 (g/cm3) 36.2 - 99.3 (MPa) a – thermal diffusivity 0.156 - 0.208 (mm2/s) tT – time of viscoplastic flow µ – viscosity factor t0 – yield stress t0 – curing time 63 - 140 (s) 42-198 (MPa) 0.20 - 2.16 (MPa) 102 - 285 (s) under pressing temperature Qp=428 °K C – cross-linking degree U – activation energy 0.85 - 0.90 (rel. un.) 6.83 - 29.40 (kJ/mol) Ks – lateral pressure ratio f – external friction coefficient 0.18 - 0.44 (rel. un.) 0.17 - 0.72 (rel. un.) under pressing pressure 56 MPa W – moisture and volatile products content isolating during pressing 0.2 - 7.0 (wt. %)

Computation of pressing parameters of frictional parts Weight mass V0 – volume of fin Pressing force Pop, top, fp – upper limits of 95-% confidence interval Time of exposure under pressure

Applied aspects of the development Developed materials Anticipated pattern of consumption of frictional materials in 2003-2005 Technical characteristics Parameter Brake materials (dry friction) Brake materials (in oils) Clutch lining materials Density 103 kg/m3 2.00-2.46 1.86-2.13 1.86-2.09 Friction coefficient (P = 1 MPa, V = 2 m/s) - dry friction - friction in oil 0.41-0.62 - -0.11-0.15 0.58-0.66 - Wear rate, Ih 10 -8 3.1-5.0 0.01 mm in 10 h 0.68-3.74 Durable thermal stability, °K, above 643 503 623 Hardness, HB, 10/250/30 17.6-46.3 7.0-19.6 19.1-26.7

Conclusions The cause of wear at outer friction in highly filled frictional materials containing structural plasticizers of non-elastomeric type is largely attributed to formation of weak boundary layers. This occurs as a result of adsorption of the liquid phase of the plasticizer on fiber and dispersed filler surfaces, which proves the adhesive mechanism of wearing of such systems. Treatment of mineral fibers as constituents of the fibrous component of frictional materials with active towards matrix polymers adhesives makes it possible to improve wear resistance, stiffness and thermal strength of the composites. Heat models of the frictional contact have been proposed to take into account redistribution of heat flows in the rubbing bodies during their interactions. As a result of intensive heat liberation at multiple braking in conditions of dry friction the actual contact area of the frictional contact has been found to diminish from 30% down to the initial contour one. This is considered to be the reason of strong inhomogeneity of temperature fields, essential rise of surface temperatures and thermal stresses in the rubbing bodies. Physical principles of conformity of processing characteristics of the polymer frictional materials to preset quality indices of final products have been formulated. Optimization of processing regimes with allowance for inhomogeneity of asbestos-free frictional materials is shown to ameliorate stability of friction parameters and reduce macroinhomogeneity of physico-mechanical properties of frictional parts.