Vol.2, No 10, 2000 pp. 1299-1317
UDC 620.17:669.14(045)
VISCOPLASTIC BEHAVIOR OF DAMAGED AISI 316H
FROM DYNAMIC EXPERIMENTS
M. Mićunović 1, M. Radosavljević 2, C. Albertini 3, M. Montagnani 3
1 Faculty of Mechanical Engineering, Kragujevac, Yugoslavia
E-mail: mmicun@knez.uis.kg.ac.yu
2 Higher Technical School , Kragujevac, Yugoslavia
3 JRC CEC, I-21020 Ispra(VA), Italy

Abstract. The group of specimens, previously subjected either to creep or low cycle fatigue, are examined by tension at 5500C in the strain-rate range [10-3, 103] s-1. The specimens previously treated by creep suffered various levels of creep strains while the specimens predamaged by LCF had various LCF strain critical cycle numbers (as a measure of initial life time). Evolution equations are calibrated for as- received, creep-damaged and LCF-damaged specimens, covering stress-strain strain-rate relations and accounting for strain and strain-rate hardening. The material constants entering the equations are damage-dependent. Comparisons with some empirical and microstructural models are made.
Key words: creep and LCF predamage, viscoplastic experiments, inelastic history, Rabotnov's delay, constitutive modelling, material constants identification

VISKOPLASTIČNO PONAŠANJE ZAMORENOG ČELIKA
AISI 316H IZ DINAMIČKIH EKSPERIMENATA
Dve grupe uzoraka prethodno izloženih puzanju ili niskocikličnom zamoru su ispitane zatezanjem na temperaturi od 5500C u širokom opsegu brzina deformacije [10-3, 103] s-1. Epruvete su prethodno izložene ili puzanju pri različitim vremenima puzanja ili niskocikličnom zamoru sa različitim deformacionim amplitudama i različitim brojevima deformacionih ciklusa. Evolucione jednačine su kalibrisane za devičanski, prethodno puzajući i prethodno niskociklično zamoren materijal. Materijalne konstante koje se u ovim jednačinama pojavljuju zavise od istorije i nivoa zamora. Uporedjenja sa nekim empiričkim i mikrostrukturnim modelima su izvedena.