Airborne Flutter Excitation System
The AFES is an electro-hydraulic inertial exciter system capable of creating controlled sinusoidal forces up to 400 lbs (1780 N) over a frequency range of 3 Hz to 15 Hz. Force is generated by the acceleration of a 250 lb (114 kg) mass by a hydraulic exciter with a 4 inch (100 mm) maximum stroke and a 600 lb (2670 N) force capability. The actuator is controlled by a dual loop controller which maintains the mass oscillating about a center position by monitoring an LVDT. while peak force is compressor controlled by monitoring the exciter’s strain gage load cell. The actuator is powered by a 3000 PSI (206 E5 Pascal), 5 GPM (20 lpm) hydraulic power supply.
The complete AFES is powered by an aircraft’s 400 Hz 125 v 3 phase power system and 50/60 Hz 120/240 v power system. System inputs consist of 28 V relay hydraulic start / stop and 1.0 V sinusoidal output from an external signal source. The system supports dwells and sine sweep testing with rates from 0.1 to 3.0 octaves per minute.
The complete system has been qualified by Wyle Laboratories, Huntsville, AL, to meet MIL-STD-810F for Rapid Decompression, Temperature, Pressure, Random vibration, and Minimum Structural Integrity Test. Calculations verified compliance with Ultimate Load Factors of 6 g (up), 12 g (down) 3.5 g (lateral) and 2 g (fore and aft) and Survivable Crash Loads of 16 g (forward).
Wyle Laboratories has certified the AEFS to MIL-STD-461E for control of Electromagnetic Interface Characteristics of Subsystems & Equipment in compliance with:
| Exciter Head | |
|---|---|
| Stroke | 4 in (100 mm) |
| Force | 600 lb (2,670 N) Hydraulic Power Supply set to 138 E5 Pascal 1,000 lb (4,450 N) Hydraulic Power Supply set to 206 E5 Pascal |
| Servo Valve | 5 GPM (20 lpm) |
| LVDT | 4 in (100 mm) |
| Load Cell | Strain gauge 5,000 lb (22,000 N) |
| Dimensions | 19″ (475 mm) length 4″ (100 mm) overall diameter |
| Weight | 42 lb (19 kg) |
| Hydraulic Oil | Mil-H-83282 |
| Hydraulic Power Supply | |
|---|---|
| Max Pressure | 3,000 PSI (206 E5 Pascal) |
| Max Flow | 5 GPM (20 l/m) |
| Reservoir Capacity | 8 Gal (32 I sealed) |
| Cooling | Air/ Oil Heat Exchanger |
| Power | 400 Hz – 125 v – 3 phase; 50/60 Hz – 120/240 v single phase |
| Start/ Stop | 28 v relay power |
| Pilot Emergency Stop | 28 v relay power |
| Automatic Shutdown & Indicators | Over temperature; Low oil level; Oil reservoir over pressure |
| Indicators | Phase correct; Blocked oil filter; Motor power applied |
| Dimensions | 31.5″ (800 mm) H x 32.9″ (835 mm) W x 49.2″ (1,250 mm) L |
| Weight | 950 lb (432 kg) |
| Overall SPL | < 90 dB |
| Pump | Variable volume pressure; Compensated motor pump |
| Cabinet Attachment Points | Aircraft seat rails |
| Master Controller | |
|---|---|
| Static Control Loop | Maintains midpoint of Exciter piston at 50 mm |
| Dynamic Control Loop | Maintains constant dynamic peak force at user defined levels during sweeps and dwells (compression control) |
| Input Sensitivity | 1.0 v peak sine = 1,780 N (linear from 0.1 v to 1.0 v) |
| Output Sensitivity of Load Cell | 250 lb/v (1,112 N/v) |
| Sweep Rate | 0.1 to 3.0 Octave/minute |
| Power | 120/240 v – 50/50 Hz (from Hydraulic Power Supply) |
| Dimensions | 14.6″ (175 mm) H x 19.0″ (475 mm) W x 25.0″ (575 mm) D |
| Weight | 53 lb (24 kg) |
| Inputs | Load cell, LVDT, Signal source |
| Outputs | Force, Displacement |
| Meters | Force, Displacement |
