SURFI-SCULPT™ - Precision controlled surface shaping

TWI has developed a technique using electron beam called Surfi-sculpt™ that enables the creation of a wide variety of surface textures through the manipulation of the electron beam. TWI has patented this technique.

The results shown are based upon a Surfi-Sculpt surface and the same or similar results may not be achieved using other surface alteration methods.

SEM images and information courtesy of TWI

Surfi-sculpt™ key points include:

• It is applicable to a wide range of materials
• Allows the creation of a range of hole and patterns
• Location of elements can be precisely controlled
• Surface modification for enhanced bonding in composites
• TWI is developing Comeld™- an advanced technique to exploit this potential

Comeld™ - Composite to Metal Joining

Introduction

The need to improve composite to metal joining crosses most industry sectors and TWI has filed for a patent that has been shown to have applications in this area.

The current application is a new composite to metal joining processes named Comeld™ where the process involves performing a treatment of the metal prior to laying up the composite.

Preliminary research, funded by TWI, has shown that Comeld™ joints have benefits over conventional joints.

Contents:

• Stainless steel/glass fibre composite joints
• Joint manufacture and tensile testing results
• Titanium/carbon fibre composite joints
• Joint manufacture and tensile testing results
• Advantages and benefits

Stainless steel/glass fibre composite joints/stainless steel 316

Joint Manufacture

Glass fibre/polyester composite and joint made simultaneously via vacuum infusion, which is a standard composite processing technique

Comeld™ joints

Control joints

Tensile Testing Results

Stainless Steel/ Glass Fibre Composite, 2 Step Joint

Tensile Testing Results

Stainless Steel/Glass Fibre Composite, 2 Step Joint

Tensile Testing Results

Stainless Steel/Glass Fibre Composite Comeld™ Joints
Energy absorbed deforming ‘proggles’

Titanium/carbon fibre composite joints

Surface Treatment - Surfi-Sculpt™/Titanium 6Al-4V

Joint Manufacture

Carbon fibre/epoxy composite and joint made simultaneously by lay-up of carbon fibre prepreg onto titanium (standard composite manufacturing technique)

Titanium

Layers of carbon fibre prepreg

Tensile Testing Results

Titanium/carbon fibre composite joints

Tensile Testing Results

Titanium/carbon fibre composite joints

Advantages

It has already been shown that:

• Comeld joints absorb more energy before failure than joints made using conventional technology
• Use of Comeld technology ensures that failure does not occur due to initial failure of the interface, which has been the weakness of traditional joints

Benefits

• Additive to existing technology
• Potential cost, time and hazard reductions in surface treatment techniques
• Potential to design joint with predictable failure mechanism
• Ability to design damage tolerant structures
• Ability to build reliable multi-material structures
• Use of composites for weight reduction in applications not previously possible
• Further weight reduction through elimination of bolts
• Ability to give composites a weldable metallic edge

Copyright TWI Ltd. 2004 Photographs and illustrations reproduced by permission