Volume 9, Issue 5 (September 1981)
A Constant Force System for Delayed Fracture Experiments
A loading system has been developed to apply constant tensile forces to test pieces for delayed fracture investigations. The basic element of the system is a high compliance ring in which the test piece is loaded across the ring diameter after precompressing the ring in a universal testing machine. Details of ring compliance and forces achievable for rings cut from readily available pipes are given and simple techniques for monitoring the applied force are described. A reduction in cross-sectional area of 30 to 40%, consequent upon effective crack growth during testing, would result in about a 1% decrease in force for a ratio of compliances of ring to test piece of 5.5 to 1.