Crack length calculation for bend specimens under static and dynamic loading

Crack length calculations in bend specimens have been derived by analyzing the sample's load-line compliance. This compliance equation is based upon calculating stiffness that incorporates the effects of shear deformation, rotary inertia and crack length in a dynamic test. Three-point bend tests for a high-strength steel and an aluminum alloy were conducted under static and dynamic loading to investigate the validity of the equation derived. The present static test results show good agreement with those predicted from ASTM E399. Dynamic crack lengths determined by the formula proposed in this work are also in good agreement with other models in the literature, and with the experimental results presented here. The applicability of the present approach to effective crack length determination under small-scale yielding conditions is discussed.