MECHANICAL PROPERTIES AT HIGH RATE OF STRAIN OF AUSTENITIC STAINLESS STEELS IN VIRGIN AND DAMAGED CONDITIONS. RESULTS AND TESTING PROGRAMME FOR CONTAINMENT OF EXTREME DYNAMIC LOADING CONDITIONS
A sound foundation of stress and/or strain criteria for the mechanical design of fast breeder reactor structures capable of bearing extreme dynamic loading conditions, passes through the experimental determination of dynamic mechanical properties of materials in end-of-life conditions with respect to the damaging processes to The results of a screening programme of tensile tests at strain rates ranging between 10**-2 and 10**3s**-1 performed on AISI 304 and AISI 316 austenitic stainless steels using small specimens (7 mm**2) showed that the dynamic response of such steels at temperatures of 400 and 550 degrees C is not univocal, passing from a substantial dynamic hardening behaviour to a dynamic softening behaviour. Furthermore the same austenitic stainless steels damaged by welding, thermal ageing and irradiation, tested at 400 and 550 degrees C showed a dynamic softening behaviour and reduction of ductility. The results obtained by testing the virgin material have been used for the calibration of the constitutive equation proposed by Perzyna which represents the material response with a reasonable agreement From the discussion of the results obtained, follows the development of a testing programme on small (up to 20 mm**2 cross section) and a large specimens (up to 5000 mm**2 cross section) focused on: - developing and calibrating dynamic constitutive equations founded on basic physical aspects, for uniaxial and multiaxial loading conditions under particular deformation and loading histories; - verifying in dynamics the existing yielding criteria, hardening rules and failure theories; - investigating by means of a high load apparatus (5 MN) defects and notches, on dynamic strength and deformation capability of large reactor structures.
Bibliographic Reference: INTERNATIONAL WORKING GROUP ON EAST REACTORS, CHESTER (UK), OCT. 10-14, 1983 - WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 31239 ORA
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Record Number: 1989122037200 / Last updated on: 1987-01-01
Available languages: en