Acoustically Transparent Underwater Adhesive

Conformal sonar systems on modern submarines are encased in a polyurethane (PU) rubber for protection and better acoustic performance. This material helps transmit sound waves efficiently and dampens unwanted noise. Damage to the smooth polyurethane surface that occurs during routine operations not only decreases its acoustic transmission, but creates turbulent noise that disrupts the sonar signal. Current underwater repair materials lack the crucial acoustic properties of the original polyurethane encapsulant. A new underwater repair material is needed that is strong, can be applied to polyurethane underwater, and matches the acoustic properties of the polyurethane to ensure effective repairs.ÝTDAís proposes to develop a unique underwater adhesive is acoustically transparent and forms a strong interfacial bond with plastics, steel, and glass. In this project, the adhesiveís strength and adhesion will be optimized, and the acoustic transparency measured using a custom-built water filled transmission loss tube (WFTLT). Proof-of-concept will be obtained by optimizing the adhesive formulation to both achieve acoustic transparency in sea water and provide the necessary physical properties (strength, adhesion, ease of application, etc.).