Stress intensity factors for cracks in some fracture mechanics test specimens under displacement control

Abstract

The stress intensity factors for cracks of varying length in some common fracture mechanics test specimens have been calculated when the displacement at the loading pins is held constant. For centre and edge cracked plates with a given crack length the stress intensity factor decreases with the decrearing separation of the loading pins. For a three-point bend specimen of span to width of 8 a plateau is observed in the stress intensity factory over a range 0.3< a/ w <0.6. For CKS-type and T-type wedge-open-loaded specimens the stress intensity factor decreases monotonically with increasing crack length for a/ w > 0.3. The implications of these results to fracture mechanics testing are discussed.