Relation Between Power and Exponential Laws of Slow Crack Growth

The coefficients V̂ 0 Q̂, and N of the power law of slow crack growth, V̂=V̂ 0 exp [–Q̂/(RT)](K/K C ) N , are evaluated in terms of the fundamental parameters V 0 . Q 0 . and B of the exponential law, V=V 0 exp [(‐Q 0 +BK)/(RT)]. It is shown that N =θ(BK C )/(RT),Q̂=Q̂ 0 −θBK C , and V̂ 0 =V 0 θ −N , where θ is a dimensionless coefficient with a value ranging from 0.2858 to 1.0, depending on the ratio of stress intensity at the fatigue limit to the critical stress intensity factor.