Composites damage & repair Find it , fix it & future proof it

Rodney Hansen, Managing Director Dark Matter Composites Ltd

• Unique perspective in looking to the future of best practice across

sectors using composite materials

• Cross Sector Worldwide Composite Customer Base

• Actively involved in designing & prototyping next generation

products with our customers

• Actively involved in training personnel to design and produce next

generation products

• Written National Occupational Standards for Composites since 2001

• Full Range of Training Solutions delivering BEST industry practices

• Only company to supply ‘tried & tested off the shelf’ equipment

solutions designed specifically for composite repair, in line with

Government/HSE guidelines for dust extraction and capture Portable

Extraction Vacuum

Tools

Composite Dust

So what do we know about composite repair?

Composite Damage & Repair Find it, fix it, future proof it

Composite Design

A creative melting pot where:

• All options are considered

• Informed decisions are made

• Compromises are made

Lay-Up

Specification

Candidate

Materials

Production

Processes

Tooling

Design

Analysis

Testing

Prototyping

Possible

Solutions

YOU ALREADY KNOW:

Most likely production

defects

NDT equipment used to

look for ‘usual’ suspects

Load capability

Likely failure modes

Damage prone areas & likely

damage

How to produce parts

=> How to repair parts

Composite Damage & Repair Find it, fix it, future proof it

Ultrasound

Laser Shearography

Tap Testing X-Ray Thermography Visual

Moisture

Meters

Knowing about likely damage in a composite part allows us to select the right equipment to find it

Composite Damage & Repair Find it, fix it, future proof it

By selecting the right inspection method (or combination of methods)

Composite repairs can be planned prior to material removal

Composite Damage & Repair Find it, fix it, future proof it

Repair surface preparation is key

Using the latest equipment developed specifically for composite repair is complimentary to using the right

NDT equipment

Numerous tools and methods are available, we have developed a key range

In 2014, a comparison of repair surface preparation methods by the UK’s National Composite Centre evaluated the DMP0110 – Step Sanding Tool Kit as: • BEST in CLASS for manual methods • More consistent surface than laser ablatement • Achieved surface accuracy within 0.025mm

DMP0110

Laser Ablatement

Composite Damage & Repair Find it, fix it, future proof it

Step Sanding Tool Kits for Composite Repair

• Consistent step sanded repair surfaces

• Prepared in less time than scarf surfaces

• Typically 50-75% time saving over

current practices

• Effective dust extraction at source

• Accommodate step sanded repair surfaces

on parts with internal and external double

curvature

• Step increments as low as 1mm (1/16”)

• Depth increments of 0.05mm (0.002”)

• Cross sector, including civil, marine,

automotive and aerospace repairs over a

range of materials

Developed primarily to remove composite

dust generated at source, resulting in

accurate repair surface preparation

Composite Damage & Repair Find it, fix it, future proof it

Knowing:

• about damage prone areas & likely damage

• what to look for & how to find it

• & how to prepare a consistent repair surface

All lead to the use of ‘Standard Repair Patches’

• Pre-made & laid up to a ‘known’ specification

• Plies pre-stacked to correct size & sequence

• Can include core materials, adhesive films and core splice

• Part specific range to accommodate changes in the

laminate in the part

• Pre-preg patches, can be ‘pressure de-bulked’ (production

consolidation of repair patch) & stored frozen

• Dry fabrics patches stitched/bound together in a combined

repair patch / resin pack

Composite Damage & Repair Find it, fix it, future proof it

Future proofing ‘Damage & Repair’ of a composite part?

Can’t be done – It is impossible to stop the inevitable

Can design a composite part to ‘Accommodate Future Damage & Repairs’:

• OEM’s could protect their intellectual property better by using production to make standard repair

patches readily available.

• Operators need simple, effective repair methods and schemes, that are easy to implement and

simplify process control of composite repairs.

• Reviewing and documenting damage and repairs to parts in use can be fed back into the design

cycle. Records often exist but are overlooked.

• Consider production verses repair, parts are in service much longer than they are in production.

Simply moving joins away from damage prone areas simplifies a repair.

• Design ‘damage prone areas’ to be more damage tolerant, easier to access or parts easy to

interchange.

• Design laminates to be ‘repair friendly’, e.g. 8 plies of a twill fabric alternating between 0º and 90º is

structurally the same as 8 plies of a twill fabric all 0º, but easier to repair