Modification of the starter turbine disk for blade containment certification tests

The paper is related to gas turbine engine starter-generator blade containment tests. The starter turbine case is expected to contain a fragment resulting from rotor fracture with the maximal level of kinetic energy. It has been proved that one third of a rotor is a fragment with the maximal level of kinetic energy. It is possible to provide this type of fracture for rotors with central holes by special trimming. However, if the disc and the shaft are a one-piece structure formation of such a fragment seems to be a problem. This type of fracture is assumed to be impossible. The aim of this work is to specify the most energy-consuming fragment in the case of possible fracture and choose a way of conducting certification tests. The method presented in the paper is based on introducing a “weak link” –local thinning- in the area under the rim. It allows separating the rim and the blades with an admissible level of kinetic energy. Some proposals for certification tests are presented.