MODE II DYNAMIC FRACTURE TOUGHNESS OF TWO HIGH STRENGTH STEELS UNDER HIGH LOADING RATE
XU Zejian; LI Yulong; LIU Yuanyong LUO Jingrun; CHEN Yuze
西北工业大学航空学院
Cite this article:
XU Zejian; LI Yulong; LIU Yuanyong LUO Jingrun; CHEN Yuze. MODE II DYNAMIC FRACTURE TOUGHNESS OF TWO HIGH STRENGTH STEELS UNDER HIGH LOADING RATE. Acta Metall Sin, 2006, 42(6): 635-640 .
Abstract Mode II dynamic fracture toughnesses K IId for high strength
steels, 40Cr and 30CrMnSiNi2A, subjected to impact loading were measured
using an experiment-number combined method. The tests were performed
on shear specimens with Hopkinson pressure bar and the time of crack
initiation was determined by strain gauge. With 3-D transient finite
element analysis, the time evolution of dynamic stress intensity factor
under different loading rates was obtained and the dynamic fracture
toughness was determined by fracture initiation time. The results show
that within the loading rate range
(2×10 6 -7×10 6 MPa m 1/2/s),
almost all the specimens failed by adiabatic shear bands and the
K IId values of the two steels increase with
increasing loading rate. The K IId value of 30CrMnSiNi2A is
larger than that of 40Cr at the same loading rate. The effect of ligament
size on fracture toughness was also discussed.
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