Multisine signal is key to test coup

The University of Glamorgan is developing jet engine testing techniques that could cut the time needed and costs involved by up to 75%. Glamorgan’s advances are a result of its use of complex multisine signals, which allow a series of signals of different and precisely-defined frequency to be used in tests simultaneously. Until now, tests […]

The University of Glamorgan is developing jet engine testing techniques that could cut the time needed and costs involved by up to 75%.

Glamorgan’s advances are a result of its use of complex multisine signals, which allow a series of signals of different and precisely-defined frequency to be used in tests simultaneously. Until now, tests have used single-sine frequency signals.The technique will test resonance and fatigue effects.

Glamorgan’s researchers have achieved average test times during trials of 617seconds for multisine signals at 30 frequency points compared with a traditional sequence of single sine tests lasting 2,140 seconds.

This produces substantial savings: tests cost £8,000 an hour for simulations of static sea-level conditions, rising to £30,000 an hour for high-altitude simulations.

Attempts to use multiple frequencies composed of simpler binary sequences were made in the 1960s and 1970s, but users were not able to set test perameters as precisely as they would have liked.

Multisine testing is particularly suitable for jet engine trials because it reduces the likelihood of results being distorted by non-linear signal variation.

Now Glamorgan university has been invited to join Rolls-Royce and the Universities of Sheffield and Birmingham in a project comparing identification techniques for jet engines.

Glamorgan has found further applications for its multisine system, most recently in tests of hydraulic actuators.