Apparatus and method for fatigue testing

A method of simulating life of a rotor blade mounting feature mounted in a complementary rotor disc mounting feature, comprising the steps of

• providing two specimen mounting features each having portions defining pressure faces matching in profile respective faces of the rotor blade mounting feature;
• providing a fixture having two opposed mounting features each having portions defining pressure faces matching in profile respective faces of the rotor disc mounting feature;
• mounting the specimen mounting features in the fixture mounting features;
• applying a first load to the specimen mounting features;
• measuring a strain in a region of the fixture between the fixture mounting features wherein the measured strain at a given time can be related to the coefficient of friction between the respective pressure faces of the specimen mounting features and the fixture mounting features at that time;
• applying a second load to the fixture, the second load being substantially perpendicular to the first load;
• controlling the second load in response to the measured strain.

An apparatus for simulating life of a rotor blade mounting feature mounted in a complementary rotor disc mounting feature, comprising

• two specimen mounting features each having portions defining pressure faces matching in profile respective faces of the rotor blade mounting feature;
• a fixture having two opposed mounting features each having portions defining pressure faces matching in profile respective faces of the rotor disc mounting feature, the specimen mounting features being mounted in the fixture mounting features;
• means for applying a first load to the specimen mounting features;
• means for measuring a strain in a region of the fixture between the fixture mounting features;
• means for applying a second load to the fixture, the second load being substantially perpendicular to the first load;
• means for controlling the second load in response to the measured strain.

An apparatus for simulating life of a rotor blade mounting feature mounted in a complementary rotor disc mounting feature, comprising

• two specimen mounting features each having portions defining pressure faces matching in profile respective faces of the rotor blade mounting feature;
• a fixture having two opposed mounting features each having portions defining pressure faces matching in profile respective faces of the rotor disc mounting feature, the specimen mounting features being mounted in the fixture mounting features:
• means for applying a first load to the specimen mounting features;
• means for measuring a strain in a region of the fixture between the fixture mounting features wherein the strain measurement means are also used to indicate misalignment;
• means for applying a second load to the fixture, the second load being substantially perpendicular to the first load;
• means for controlling the second load in response to the measured strain.