Analysis of cracked and un-cracked semicircular rings under symmetric loading

• Edge cracked semicircular ring (ECSR) is analyzed as compression fracture specimen.
• Elasticity solutions of uncracked semicircular ring and its extreme case are obtained.
• FE results of ECSR(Ch) show enhancement of KI over earlier designs.
• Form factor constancy of ECSR(Ch) is investigated.
• Four point bend specimen is shown to be an extreme case of ECSR.

Edge cracked specimens have been widely utilized for fracture testing. Edge cracked semicircular disk (ECSD) specimen has now been well characterized with regard to its form factor and weight function. This paper presents a modified semicircular ring version of this specimen to enhance the form factor in general while retaining other desirable features. The efficacy of the modified design is proved by combining theory of elasticity solutions with finite element results to arrive at the optimum design geometry. New insights emerging from this work are used to theoretically re-examine the arch-tension and the four-point bend specimens.