Honeycomb Sandwich Design Technology 6p3342

HONEYCOMB SANDWICH DESIGN TECHNOLOGY

MECHANICAL ENGG. (4TH YEAR)

HONEYCOMB SANDWICH DESIGN TECHNOLOGY

INTRODUCTION MATERIAL DESIGN MANUFACTURE APPLICATIONS

INTRODUCTION Honeycomb structures are natural or man-made structures . The cells are often columnar and hexagonal in shape. The strength of laminated or sandwich s depends on the

size of the . The material takes its name from its visual resemblance to a bee's honeycomb - a hexagonal sheet structure.  The core resists the shear loads, increases the stiffness of the structure.

MATERIAL The following criteria should be considered in the routine

selection of core, facing, and adhesive. In Structural Considerations such as strength, stiffness, adhesive performance, economical consideration. In Environmental Considerations such as temperature, Heat Transfer, Flammability, Moisture/Humidity. In Mechanical Performance we consider cell size, cell shape, skin materials, adhesive materials. Generally we use material for honeycomb core is graphite polyimide, aluminium, glass polyimide, polyurethane foam.

DESIGN LOADS: The applied load creates a bending moment which is a maximum at the fixed end, and a shear force along the length of the beam. DEFLECTIONS: The bending deflection is dependent on the relative tensile and compressive module of the skin materials. The shear deflection is dependent on the shear modulus of the core. Total Deflection = Bending Deflection + Shear Deflection

FAILURE MODES

Designers of sandwich s must ensure that all

potential failure modes are considered in their analysis. Strength

• Stiffness

 buckling

• Shear crimping

Skin wrinkling

• Intra cell buckling

MANUFACTURE Basic Honeycomb Sandwich Production Methods Heated Press, generally used for the production of flat board

or simple preformed s.  Vacuum Bag Processing, used for curved and complex form s. Matched Mould Processing, used generally for batch production of finished s

Heated Press

Vacuum Bag Processing

Matched Mould Processing

APPLICATIONS

Aerospace Aeronautical Naval Automobile Etc.

Aerospace 1. Fairings: Carbon prepregs. Aluminium honeycomb and adhesives. 2.External Payload Carrier Assembly(SPELTRA): Carbon prepregs, aluminium honeycombs and adhesives. 3.EPS Ring: Epoxy/carbon prepreg or RTM. 5.Booster Capotage: Epoxy glass/non-metallic honeycomb. 6.Yoke: Epoxy carbon filament winding .

Aeronautical

1.Radar Transparent Radome: Epoxy or BMI Prepreg or RTM resins And woven preforms (socks). 3.Fuselage Sections: Epoxy carbon Prepregs. Non-metallic Honeycomb core and Redux adhesives. 10.Flying Control Surfaces: Epoxy carbon and glass Prepregs. Honeycomb Core material and Redux adhesives.

Naval 2.Hull Skin Structure: Prepregs, engineered fabrics, honeycombs. 4.Suspended Ceilings: Lightweight sandwich s/honeycombs. 7.Accommodation Cabin Units: Lightweight sandwich s, Prepregs and honeycombs. 9.Weather Shield: Prepregs and honeycombs. 10.Communications Equipment: Prepregs and honeycombs.

Automobile Chassis of Ferrari F50:

Nomex honeycomb core, sandwich construction. Chassis of DOME F150: Carbon fibre/ aluminium honeycomb sandwich monocoque. Bluebird-Proteus CN7: Advanced aluminum honeycomb sandwich of immense strength.

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