Experimental study of thermal sliding contact parameters at interface seat of large strains

Abstract

The study relates to the characterization of thermal sliding contact work piece-tool under great deformations, representative of the secondary shear zone of a High Speed Machining Process (HSMP). The literature shows that the authors consider a perfect thermal contact condition and suppose that the heat flux generated by friction at the sliding interface is divided in the ratio of the thermal effusivities of materials in contact. However the distribution of the normal stress at this interface is large and the thermal contact must become imperfect before the release of the chip. The improvement of HSMP simulation requires the checking of these two assumptions. The proposed experimental approach is founded on temperature field measurement by thermocouples in order to estimate thermal sliding contact parameters at the part/tool interface seat of heat dissipation in same condition as the HSMP: the thermal contact resistances RTC, the generated heat flux φ _g and share ratio α of φ _g . Experiments were carried out on friction device that reproduces mechanical and thermal contact conditions of a HSMP at the tip tool. The experimental plan allows to study the influence of sliding speed and materials in contact on the thermal parameters. Results show that heat flux is divided into the ratio of the thermal effusivities of materials in contact but the thermal contact is systematically imperfect.