Experimental and Numerical Evaluation of Momentum Variations Effect of Striker on Fracture Energy in Charpy Impact Testing of API X65 Steel

In this study investigated the effects of momentum variations on fracture energy in Charpy impact testing of API X65 steel by experimental and numerical methods. Experimental analysis was conducted in the various speed of impact about 3.50 to 5.72 m/s and impact energy varied about 450 to 1200 J. The experimental results showed that increase of about 63% in impact speed increased the fracture energy about 15%, because of material properties dependence on loading rate. Numeral studies were performed in two categories with ABAQUS software. First mass variation in constant velocity assumed standard quantity about 5.5 m/s in which impact energy varied about 300 to 1200 J and the second, velocity variation with constant mass assumed 50 kg that impact energy varied about 625 to 1600 J. The simulation results showed the variations in mass had not any effect in fracture energy and in all analyses, it was about 265 J. However, increasing the velocity variations with constant mass, caused a slight reduction of about 5% in the fracture energy. The reason for the difference between experimental and numerical results is the lack of consideration of the effect of strain rate on mechanical properties of tested steel in numerical analysis.