DRDO First Composite Sonar Dome For Naval Warships,Indian Armed Forces,Wiki
Sonar dome is a protective cover to sonar equipment of surface war ships.It is designed by Defence Research and Development Organisation (DRDO) of India.
This sonar dome is a unique initiative, which has been manufactured by a composites manufacturing company in India and can be seen as a significant contribution by the Indian industry to the ‘Make in India’ movement.
The Research & Development Establishment (Engineers) [R&DE(E)], a Defence Research and Development Organisation (DRDO) laboratory based in Pune, has developed a sonar dome :a protective cover for sonar equipment of surface warships.
Defence minister Manohar Parrikar will flag off a huge bow mounted sonar dome at Defexpo site in Goa on March 29. DRDO director general Dr S Christopher, who is also the secretary, department of defence (R&D), will be present on this important occasion. The dome will be delivered to Mazgaon Docks in Mumbai.
Design and Development
The dome is designed to house sonar array, and to maximize the performance of the array by reducing the effects of noise of water turbulence and protecting the array from wave slamming, minor collisions etc.
In the design of sonar dome, both structural and acoustic considerations come into play. Typical structural constraints may include the deformation of the structure under steady external flow, accelerations, slamming loads and shock loads. From an acoustic stand point of view, the goal is to maximize the fidelity of incoming sound by ensuring that the self-noise and flow induced noise can be inherently minimized.
The Current Sonar Domes in advanced composited bring additional benefits for stength and acoustic performance, e, extending the ability of the vessel to locate, evade and engage hostile environments. The sonar dome is mounted at the bow of the ship.
The Compisites Sonar Dome consists of Stiffeners,acoustic window area (acoustically sonar drones) baffle plate, and flange with gasket for water tight connection of the dome to ship. Acoustic window area is a composite-rubber sandwich construction. Lifting hooks are provided for handling dome during handling and fitting.
A sonar array is fitted below the waterline to all anti-subamarine warfare (ASW) ships, which will function as the vessel’s navigator under water. The dome is fitted over the sonar array in order to ensure that its electronics and sensors are not exposed to the hostile environment in its surroundings. The dome must be structurally sound and also acoustically transparen
R&DE(E) Manufacturing Process in making Sonar DOME:VARTM and RFI
R&DE(E) has established two manufacturing processes, Vacuum Assisted Resin Transfer Molding (VARTM) and Resin Film Infusion (RFI) for realization of large composite structures. Either of them can be used for realization of composite sonar dome. Both the processes require mold for realization of a structure.
Since RFI is a high temperature curing process, it requires oven for curing or a heating system embedded in the mold. Whereas, VARTM can be a room temperature curing process, hence may not require any oven or heating system for curing.
To realize sonar dome, male or female mold may be used depending on factors like dimensional accuracy, surface finish, ease of lay-up, demolding etc. Type of mould shall be chosen depending on the merits and demerits of the process and finished product requirements
In VARTM process, vacuum and resin points are provided for creating vacuum and sending resin into dry fabric, respectively. These points are decided based on guidelines obtained from process modeling and flow simulation studies.
In VARTM process, resin is sucked under vacuum and it flows into the dry fabric until it is saturated with resin. To monitor resin flow online in complex regions, a process monitoring system is also available which can be deployed wherever necessary. After resin infusion, job is allowed to cure at room temperature for 24 hr then the job is demolded. Thus the complete design to manufacturing know-how of composite sonar dome is available with R&DE(E) and can be transferred to interested industry partner for commercial use.
Article Source :Drdo.gov.in