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The sandwich type structure is commonly employed in helicopters due to its advantages in terms of:

  • A

    Low mass and low stiffness.

  • B

    Ease of deformation under load.

  • C

    Low mass and high stiffness.

  • D

    High temperature resistance.

Refer to figures.
A sandwich structure consists of two thin, high-strength face sheets (usually made of composite materials or metals) that are separated by a low-density core material (such as foam, honeycomb, etc.). This design creates a structure that has an excellent balance between weight (mass) and stiffness, making it a preferred choice for various components in helicopters due to the following reasons:

  • Low Mass: The core material used in sandwich structures is typically lightweight, which significantly reduces the overall weight of the component. In aviation, reducing weight is critical as it directly affects fuel efficiency, performance, and payload capacity.

  • High Stiffness: Despite its low mass, the sandwich structure exhibits high stiffness and strength due to the rigid face sheets. The face sheets carry most of the structural loads and provide resistance to bending, buckling, and other mechanical stresses.

  • Ease of Deformation Under Load: While the sandwich structure is stiff and resists deformation, it also possesses some flexibility. This characteristic allows the structure to absorb and distribute loads efficiently. During flight or when subjected to external forces, the sandwich structure can deform slightly, dissipating the energy and preventing sudden, catastrophic failure.

  • Vibration Damping: The core material in the sandwich structure acts as a vibration damper, reducing the propagation of vibrations and noise throughout the aircraft. This enhances passenger comfort and reduces fatigue on various components.

  • Thermal Insulation: The core material's low thermal conductivity provides some degree of insulation, helping to regulate internal temperatures and protect sensitive equipment from extreme environmental conditions.

Therefore, a sandwich type structure is often used in aircraft because of its “low mass and high stiffness”.

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