Multi-axial low-cycle-fatigue test rig

Abstract

A multi-axial rig for testing aircraft gasturbine compressor and turbine disks is described. The rig is based on the closed-loop electro-servo hydraulic control principle. This principle combines the use of hydraulic and electronic components not only to control the loads but to hold the true disk position. Nonrotating disks can be loaded to produce stresses which closely simulate loading experimenced by disks in service. Disks with up to 100 loading points and with diameters between 2.5 in. and 18 in. are acceptable within this framework, with loads up to 25,000 lb per loading point, at frequencies up to 7 Hz, and at temperatures in excess of 1500°F. The rig has demonstrated its effectiveness as a useful laboratory tool for compressor and turbine-disk low-cycle fatigue and cyclic stress-rupture life evaluation.