Acoustic testing techniques for replicating in-flight dynamic loads.

Area of Science:

• Aerospace Engineering
• Mechanical Engineering
• Acoustics

Background:

• Combat aircraft weapon systems feature complex electronic assemblies operating in harsh dynamic environments.
• Aerodynamic noise is a primary excitation source impacting these systems during flight.

Purpose of the Study:

• To compare different acoustic laboratory testing configurations for simulating flight-induced vibrations on weapon system electronic assemblies.
• To determine the most adequate testing method for replicating in-flight vibratory responses.

Main Methods:

• Vibroacoustic measurements were collected during captive flight tests.
• Laboratory acoustic testing was performed in a reverberant chamber using two configurations: enclosed and exposed.
• Acceleration responses were measured for both configurations under simulated in-flight acoustic levels.

Main Results:

• The exposed configuration showed significantly lower acceleration responses compared to flight measurements.
• The enclosed configuration, despite acoustic attenuation by the structure, yielded higher acceleration responses closer to flight data.
• This indicates the enclosed setup better simulates the vibratory response to flight loads.

Conclusions:

• The enclosed acoustic testing configuration is more effective for simulating the vibratory response of weapon system electronic assemblies to flight loads.
• Accurate simulation requires considering the structural shell's influence on acoustic excitation and vibration transmission.
• This research informs the development of more realistic and reliable testing protocols for aerospace electronic systems.