AUTOMATIC SYSTEM FOR MEASUREMENTS OF INTERNAL FRICTION AND ELASTIC MODULI

30 KHz) e s t dktectke par une mgthode electrostat ique avec modulation en friiquence e t stockhe en appliquant une conversion A/D (12 b i t) rapide. Cela rend possible des m6sures de frottement interne dans une game de Q-1 = jusqu'b 10-l. Des exemples exp6rimentaux sont prhsent6s pour montrer l a puissance e t l 'universa l i th du syst6me. Abstract- A versa t i le computer controlled automatic resonant bar system has been developed for measurement of internal f r ic t ion and e l a s t i c moduli in a wide temperature range of 10K t o 1300K. The decaying oscil lat ions (100 Hz t o 30 KHz) are detected e lec t ros ta t ica l ly by the frequency modulation technique and stored using high speed buffered 12 Bit A/D conver ion enabling internal f r ic t ion to be measured in the range Q-1 = 10-6 to 10-j. Examples of measure-ment are presented to show the capability and ve r sa t i l i t y of the system. The resonant bar technique i s well known for a long time as a classical method for the investigation of the e l a s t i c properties of solids. The resonance frequency of