Ultrasonic Inspection of In-Service Composite Bicycles and Components

Transcription

1 Ultrasonic Inspection of In-Service Composite Bicycles and Components Cyclitech 6-7 Dec 2016 Raoul Luescher Director Luescher Teknik Pty Ltd

2 Personal Background Diploma of Mech Eng Level 2 NDI technician since Held FAA, CASA, Mil, etc. certifications. Previously employed by Boeing, Aust Institute of Sport, Composites CRC. Built first carbon bike Founded Luescher Teknik

3 Luescher Teknik Specialist Sports Technology Malvern Star Oppy Carbon Bikes. BC Tammar MTB Enduro Rim. Range of consulting roles. Assess and Repair Division 2009 We have assessed over 3200 carbon bicycle frames and parts. Clients include: Insurance Brands Distributors Shops Public 3

4 What is NDI? Non Destructive Inspection To inspect materials or parts without detriment to it s function or performance. Provides information on product integrity and reliability. Maintains predictable quality and product performance. In service safety. 4

5 NDI Methods for Composites Common methods: Ultrasound Radiography (X Ray) Acoustic Emission Thermography Tap Test Visual Inspection 5

6 What is an Ultrasound Scan? In simple terms, a sound wave is sent into a material, the sound energy transmitted or reflected back is measured to provide information on the materials continuity. 6

7 Why use Ultrasound? Reliably finds typical flaws and damage in laminar materials. Aerospace standard method. Relatively low cost. Safe to use. Quick 7

8 Types of Ultrasound Many types and methods Through transmission. Pulse echo. Compression wave or shear wave. A-Scan. B- Scan. C scan. 8

9 Ultrasound Scans Ability to identify the defect type. Delamination. Voids. Porosity. Unbonds. Wrinkles. Inclusions. 9

10 In-Service Ultrasound A-Scan Pulse Echo. Portable. Quick. Suitable for variable geometry. Experience required. No hard copy or image. 10

11 A Scan Pulse Echo Single side access only required. Variable geometry and contour. No image. Interpretation of oscilloscope trace. Experience required. 11

12 Typical Ultrasound equipment A-Scan. Compression wave. Mostly Pulse echo. High frequency. Small transducer. Portable. 12

13 Why not use a Tap Test? Unreliable for laminate testing. Geometry affects response. Size of flaw difficult to assess. 13

14 The Need for NDI Damage or production flaws are often found to contribute to an in service failure. In many cases there is no visual indication of a serious flaw leading to a potentially catastrophic structural failure. This may lead to injury or death of the cyclist. 14

15 Effect of Flaws Flaws such as voids or porosity significantly reduce material properties. 2% increase in voids can reduce properties by 20% or greater. Void content has been shown to be a major consideration in composite materials' quality control, regardless of the loading mode. 15

16 Consequences Flaws reduce the material properties. Design load capacity versus actual load capacity. Data shows impact damage is more likely and greater if flaws present. 16

17 Our Statistics Damage Statistics Crash Other Manufacturing Handling Searchable Database installed Aug Items scanned. Other includes: Chain drop. Tyre rub. Hanger failure. Handling includes: Roof rack. Transport. Workstands. Overtightening. 17

18 Statistics - Comments Crash damage most common. Seat stays and top tubes. Manufacturing flaws can be associated with delamination from impacts. Fork steerers often have delamination after a frontal crash, often not visible. Tyre rub wear on the stays common with wider tyres. 18

19 Examples 19

20 Fork Steerer Manufacturing planar voids and porosity. Middle of steerer. Poor compaction. No visible indication. Scrapped. 20

21 Fork Steerer Manufacturing planar voids and porosity. Several areas. Passed CT scan. No visible indication. Scrapped. 21

22 Fork Crown Planar voids. No visible indication. Adjacent porosity. High load area. Scrapped. 22

23 Fork Crown Wrinkles. Porosity. Variable wall thickness. Load path??? Scrapped. 23

24 Fork Steerer Involved in a crash. Delamination at the rear face at the headset and stem clamp area. Probable voids and porosity in the area. No visible indication. Scrapped. 24

25 Fork Leg Resin dry. Loose fibres. Difficult to find with most NDI methods. Scrapped. 25

26 Frame Seat Stay Impact. Is it damaged or not? Common impact when derailluer hanger fails. 26

27 Frame Chain Drop Chain stay gouge. Delamination is significantly larger than visible damage. Repair. 27

28 Frame Chain Drop Sometimes there is only paint damage. No structural damage found. 28

29 Frame Joint Lug joint crack. Considered by factory as a paint crack. Warranty rejected. 29

30 Frame Joint Frame lug joint crack. Large adhesive void found. Heavy wrinkling adjacent to the joint. Scrapped. 30

31 Frame Top Tube Bridging voids. Crack visible at the first indication. Would the frame have sustained the load without failure with no voids present? Repaired. 31

32 Frame Top Tube Combined delamination and planar voids. Large area. Impact associated with production flaws. Scrapped. 32

33 Frame Down Tube Caused by roof rack carrier clamp. Delamination. Barely visible surface indication at tube corner. Repaired. 33

34 Frame Down Tube Laminate porosity. Large areas. Similar area in the Top Tube. No visual indication. Scrapped. 34

35 Frame Down Tube Crash. Brake caliper impact. Delamination. No visible damage. Repaired. 35

36 Frame Seat Tube Rider concerned about the crack indication. Front derailluer clamp delamination. Crack indication verified as a paint scratch. Repaired. 36

37 Frame Cable stops Delamination around drill holes. Poor drilling and incorrect rivets can delaminate, especially thin UD. Repaired. 37

38 Frame Wall thickness variation: Resin pooling. Variable compaction. Fibre wrinkles. Common to present as fatigue cracks over time. 38

39 Wheel Rim Impact at rim edge. Delamination much larger than visual indication. Delamination extending to drill hole. Scrapped. 39

40 Wheel Rim Impact at rim sidewall. Skin to core disbond. Small visual indication. Repaired. 40

41 Handlebar drops Planar voids. Poor compaction. Large area of voids. This bar failed in use at the other side. 41

42 Handlebar Stem clamp area. Planar void. Delamination from overtightening. Combination of flaw and load. No visible indication. 42

43 Handlebar Stem clamp area. Delamination from over tightening. Slight depression on surface. Scrapped. 43

44 Summary Flaws are mostly a process problem. Better quality assurance is required. Delamination is often not visible on the surface. Typically the warranty applies AFTER the part has failed! After failure evidence of a flaw can be difficult to find. 44

45 Production NDI Process control. Reduce failures. Customer care. Brand reputation. Reduce recalls. Reduce warranty claims. Reduce liability claims. Reduce costs. Photo: Mike Prendergast 45

46 Questions? Check out the Websites Raoul can be contacted by at 46 LUESCHER TEKNIK PTY LTD 2016