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SOURCE: MONEY CONTROL

Extensively used in almost all spheres of engineering, on land, air or water, composite materials have been generating a lot of interest and finding widespread use, especially in the defence sector. A combination of two or more materials with different properties that perform specialised jobs, composites are high-performance materials used in almost all industries. The defence sector is one of the major users of composite materials, particularly for rockets, missiles and other equipment.

Composite and laminates are used in making missile parts as they are often lighter, stronger, and more durable than metals or other materials. Here is low down on composite materials and their use in the defence sector:

What are composite materials? 

A composite is a structural material that consists of two or more constituents that are intimately bonded together to form an integrated structure. The load-bearing constituent is called “reinforcement” and the one in which it is embedded is called the “matrix”. For a structural composite, the “reinforcement” is usually glass or carbon fibre and the “matrix” is a thermoset polymer such as epoxy. 

Unlike metals, composites do not corrode and have a high strength-to-weight ratio and high stiffness-to-weight ratio. Hence, they are used for applications in virtually all sectors of engineering—land-based, marine, or aerospace.

How are composite materials better than conventional materials in rocket technology?

Composites are better because of their high specific strength and high specific modulus. They do not corrode like metals, nor do they undergo catastrophic failure. Composites offer a wide range of properties by having a combination of different reinforcing and matrix materials. 

Multiple functionalities such as stealth, health monitoring, etc can be incorporated in situ, which is usually not possible with metals. 

Moreover, composites are high-performance materials that are lighter but stronger and stiffer than their corresponding conventional materials. As a result, specific advantages like longer range, larger payload, reduced cycle time, reduced cost and such other characteristics can be achieved.

Do composites have a bearing on India’s efforts to step up the indigenisation of its weapons programme?

Indigenous development of weapons is associated with high performance. Hence, composites are essential in certain areas. Composites are currently in use in many Indian weapons programmes. The airframe of LCA (light combat aircraft), superstructures of naval vessels, components for various strategic and non-strategic missile systems are a few examples. 

Multi-functional composites for armour application, aerospace composites with functional features such as radar transparency, stealth, etc are being developed fully indigenously. Similarly, several niche products have been indigenously developed. One example would be the first indigenous composites sonar dome developed by Pane-based R&DE (E).

What is the history of composite making in DRDO? What were the main challenges?

DRDO laboratories based in Pune, Hyderabad and Bengaluru have been developing composite structures for all three services for more than two decades. The aerospace-related product development by ISRO, CSIR and DRDO labs took the lead in establishing manufacturing processes and industries for product development. 

R&DE (E), Pane has done pioneering work in establishing processes for product development related to naval and land applications. Examples of this effort are carbon fibre reinforced bridges of different spans for the army that are 40 percent lighter in comparison to their metallic counterparts. Glass fibre-reinforced armoured vehicle hulls with integral ceramics armour have also been developed. 

The main challenge is the paucity of industry support for manufacturing high-end military-grade composites products.