PROGRESSING WITHIN AMPLITUDE DOMAIN MECHANICAL SPECTROSCOPY - OVERCAME DIFFICULTIES AND REMAINING QUESTIONS

Amplitude domain mechanical spectroscopy is specially interesting as i t yields material response data directly in terms of stress or strain amplitudes. Critical stresses and strains are the most immediately sig nificant parameters when material strength is the main object of inves tigation. On the other hand, as the phenomena are non-linear, no full rigorous treatise of the complex question of amplitude dependent (mate rial) damping (ADD) and modulus is presently available, as far as we k now. However the existence of certain particular, reproducible feature s of ADD suggest that a systematic analysis of amplitude dependent dam ping curves (ADD curves) could be carried out by an ad hoc semi-empiri cal procedure. This procedure, called 'parametric analysis', enables a very precise determination to be given of the various components of A DD. It is thus a means of performing amplitude domain mechanical spect roscopy. An associated model, called 'moties-pinners model' proposes a n outline for frequently observed phenomenology in terms of microstruc tural effects. We shall try here to specify which elements of the trea tise can be considered as established and which still require further investigation.