Underwater Acoustic Materials

From the inception of Syntech, it was realized by the founders that the properties of syntactic foam could be tailored to yield a variety of underwater acoustic characteristics, such as transparency, absorption, reflection, and refraction. This work has led to a family of materials that are being employed in various underwater applications, such as acoustic windows, anechoic test tank linings, and transducer isolators and decouplers. Our in-house acoustic test facility is designed to characterize these products across a broad range of frequencies.

The following outlines the various product lines with acoustic characteristics:

Anechoic Materials - The SADM and SYNAB Group: Through a Small Business Innovative Research program sponsored by the US Navy, the inherent mechanical properties of syntactic foam were developed into an underwater sound-absorbing composite capable of withstanding high hydrostatic pressures. This work led to the group being employed primarily as anechoic test tank liners and unique sound attenuating structures. Using the same proven technology, a secondary class of wedge-shaped anechoic materials, the SYNAB group, were designed as a cost-effective anaechoic lining for low frequency acoustic test tanks and pools.

Transducer Baffles and Isolators - The SATB Group: Early in the development of our anechoic materials group, it was realized that much of the prior research in this area was directed at transducer applications. The SATB group was developed using the same proven anechoic materials technology applied specifically to transducer isolation and decoupling requirements. Several of the most innovative sonar systems currently being developed take advantage of the unique properties of these materials.

Acoustic Windows and Lens Applications - The AFC Group: A few grades of standard syntactic foam possess an inherent specific impedance match to seawater. These buoyant materials exhibit very low attenuation coefficients below 1MH, which makes them ideal candidates for tough, high-strength acoustic windows. Their inherent high sound velocities also provide the required refractive properties for acoustic lens applications. Materials may be sold in standard block sizes or cast to a custom shape.

Standard Buoyancy Foams: Some standard syntactic buoyancy foams manufactured by Syntech Materials may be applicable in alternative areas of underwater acoustic noise control, especially above 1 MHz. The buoyant, high-strength materials, especially our low-density syntactic foams, are successfully being used as pressure release materials in a variety of transducer assembly applications.

Syntactic Acoustic Damping Material & Syntactic Acoustic Transducer Baffle

Syntech Materials, Inc. combines syntactic foam technology with advanced acoustics theory into a novel class of underwater sound attenuators. These materials, known as the SADM and the SATB families of syntactic foams, have repeatedly shown high levels of echo reduction and insertion loss over the 10 KHz - 100 KHz range, both at ambient pressure and at operating depth. Two types of materials are available: -1 series for broadband attenuation and -0.5 series for improved performance at higher frequencies (above 30 KHz). These materials have been found to be extremely effective in a number of underwater acoustic applications. SADM has been used extensively as an anechoic acoustic test tank lining. SATB is designed for use as a transducer isolation mounting material. Acoustic characterization graphs are available which detail the transmissive and reflective properties of flat test panels.

SYNAB-F is a structural acoustic absorbing material which provides three unparalleled performance characteristics as an anechoic coating:

• Broadband Attenuation
  
  
• Positive Buoyancy
  
  
• Non-Toxic Formulation

Additionally, the material's unique composition makes use of abundant recycled filler materials and a proprietary manufacturing process, resulting in a revolutionary, low cost acoustic absorbing material for a variety of underwater applications. Available acoustic characterization graphs represent the transmissive and reflective properties of the material at ambient conditions and under hydrostatic pressure (1500 psi).

Two grades of syntactic foam have been developed which are impedance matched to seawater. They can be cast and machined to customer specific requirements.

ACF-38: 38 lb/cubic feet low cost seawater impedance matched foam

ACF-40: 40 lb/cubic feet premium seawater impedance matched foam