Experimental Investigation of Tearing Instability for Reactor Pressure Vessel Steel (A 508 cl. 3)

Experimental investigation has been conducted to make clear the effects of initial crack length and loading system compliance on the tearing instability phenomena, J-integral fracture tests of A508cl.3 steel have been performed on compact specimen in a test machine which employed coil spring to produce high testing compliance. Tearing crack velocity was measured by using crack depth indicator. Results were analysed with respect to material and applied tearing moduli. Most stable-unstable behaviors are in good agreement with theoretical prediction. Loading system compliance and initial crack length have notable influence on J-integral at instability point and also maximum crack velocity.