FIGURE CAPTIONS
FIGURE 1 Microstructure of the AISI 5140 steel
FIGURE 2 Experimental true stress-strain curves of the AISI
5140 steel
FIGURE 3 Yield strength of the AISI 5140 steel at different
strain rates
FIGURE 4 Load-deflection curves of quasi-static specimens
FIGURE 5 Load-deflection curves of Charpy impact specimens
FIGURE 6 The experimental incident and reflected strain waves
FIGURE 7 Crack initiation signals of the test specimens
FIGURE 8 Displacement of the incident bar end initially in
contact with the specimen
FIGURE 9 Finite element model of the incident bar, the specimen
and the support
FIGURE 10 Numerical J -integral history at the crack tip
FIGURE 11 Fracture appearances of AISI 5140 steel. (A)
quasi-static test, (B) instrumented Charpy impact test, (C) HPB impact
test
FIGURE 12 Fracture toughnesses of the AISI 5140 steel under
different loading rates
FIGURE 13 Failure assessment diagram of the AISI 5140 steel.
(A) effect of loading rate, (B) effect of strain rate