Strength Mismatch Effects on Charpy Absorbed Energy and CTOD Fracture Toughness

Abstract

In order to examine the difference between the sensitivity of Charpy absorbed energy, V E, and critical CTOD, δ cr , to strength mismatch in welds, the numerical analysis was conducted. This study adopted the evaluation method based on the Weibull stress criterion for calculation of V E and δ cr assuming that the critical Weibull stress at brittle fracture is independent of the strength mismatch as well as the loading rate. This analysis showed that the V E and δ cr decreased as the location of the V-notch or crack approached welded interface. The change in V E was larger than that in δ cr , because the strength mismatch caused acceleration of strain rate and decrease in temperature rise near the V-notch as well as plastic constraint. This result indicates that the sensitivity of the V E and δ cr to strength mismatch is different depending on the loading rate.