S18  Processos Mecânico-Metalúrgicos    Titulo: MEDIÇAO IN-SITU POR ULTRASOM DA ÁREA REAL DE CONTATO EM PROCESSOS DE CONFORMAÇAO DE METAIS   Resumo : IN ORDER TO GIVE A MORE ACCURATE THEORETICAL DESCRIPTION OF FORMING PROCESSES, IT IS IMPORTANT TO IDENTIFY INFLUENCES AND TO INVESTIGATE A SUITABLE PHYSICAL MODEL. IN SUCH A MODEL THE REAL CONTACT AREA AT THE INTERFACE BETWEEN TOOL AND WORKPIECE PLAYS A KEY ROLE. THE METHOD DEVELOPED ALLOWS FOR THE SIMULTANEOUS MEASUREMENT OF THE REAL CONTACT AREA (BY AN ULTRASONIC TECHNIQUE), THE SHEAR STRESS AND THE FRICTION COEFFICIENT IN DEPENDENCE ON THE NORMAL STRESS AND THE RELATIVE SLIDING LENGTH. THE REAL CONTACT AREA AND THE FRICTION COEFFICIENT WERE INVESTIGATED FOR STEEL SHEETS SPECIMENS UNDER LUBRICATION BY AN COMBINED TWIST AND COMPRESSION TEST. KEYWORDS: REAL CONTACT AREA, FRICTION, ULTRASOUND, NON DESTRUCTIVE TESTING, FORMING     Autores : BATALHA, GILMAR FERREIRA ENGEL, ULF 0 GEIGER, MANFRED 0 NEUDECKER, Thomas 0     Trabalho Completo :   COBEM99 | Comissão  Organizadora | Palestras | Sessões Técnicas | Autor | Simpósios e Sessões Especiais | Revisores |  Título  dos  Trabalhos | Local