GROWTH AND COALESCENCE OF MULTIPLE CRACKS – EXPERIMENTS AND FRACTURE MECHANICS BASED MODEL

Short crack growth tests are carried out on the coarse-grained nickel-based cast alloy Iconel 100 (IN100) and two microstructures of the austenitic stainless steel AISI 347 using the replica technique. IN100 is tested under TMF and AISI347 isothermally. For both materials, several cracks are found which grow together to form the final main crack. Atypically, the final main crack length does not develop exponentially. To describe the damage evolution of the final main crack, a model is developed based on inelastic fracture mechanics, which includes the different crack driving forces along the crack front, and applied to the test results.
EXTENDED ABSTRACT