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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