Smart anechoic materials for acoustic signature control

Anechoic materials fitted to submarines and other similar platforms, such as torpedoes, can absorb and scatter acoustic energy, therefore reducing the probability of detection by an enemy's active sonars.

Our project aims to develop a new class of anechoic materials that can passively minimise the acoustic impedance mismatch at the material-water interface and, in turn, reduce the reflected sonar signal.

Competitive advantage

The anechoic materials under development in this project consist of a porous rubber template infused with proprietary supercritical fluids. These fluids have been designed to:

• Match the impedance and speed of sound in sea water, providing high compliance (low acoustic impedance mismatch) and significantly reducing the reflected sonar signal
• Give the anechoic material a self-tuning ability in response to the submarine manoeuvres as it dives or ascends through water

Successful applications of research

Successful application of the research outcomes to Australian Defence Force submarines and subsurface weapon platforms will:

• Significantly reduce their acoustic signatures Enhance their battlefield survivability
• Prevent the enemy from deploying its sonar assets at a safe distance from Australian Defence Force platforms, therefore degrading the enemy's ability for active sonar detection

Partners

• Defence Science and Technology's Maritime Division

Impact

• Application of the anechoic materials under development in this project to the Australian Defence Force submarines and other subsurface assets will lead to a step-change reduction in the target echo strength of these platforms; th is not only makes detection by active sonar systems much more difficult, it also reduces the range at which detection is achievable

Capabilities and facilities

• Extensive laboratory facilities and technical expertise for the formulation, production and testing of supercritical fluids of interest under realistic conditions
• Our laboratory facilities include a state-of- the-art fluid/surface interaction cell capable of maintaining pressures up to 60MPa

Professor Behdad Moghtaderi