Using Thermal Imagery to Inspect Damaged Carbon Bicycle Frames
If a carbon bicycle frame has been damaged, does the damage go beyond the area that you can see? The simple answer is "Yes". Carbon fibre is highly susceptible to a phenomenon called Barely Visible Impact Damage (BVID). The carbon fibre looks fine on the surface, but the structural integrity of the carbon fiber matrix has jeopardized. The amount of nonvisible damage will depend on the force and the type of impact. This BVID damage may exist as delamination or cracking within the carbon wall of the bicycle frame, and may propagate over time resulting in a catastrophic failure.
The non-destructive testing method utilizing a thermal camera using an induced low voltage current measures the electrical resistivity of the carbon to identify any nonvisible damage. This method does not harm or stress the carbon frame and allows potential dangers to identified for repair before failure.
If a frame's carbon tube is damaged, the damage may be visible, but the damage goes well beyond this area. The thermal camera quickly identifies damage that is not visual, and highlights areas of delamination and cracking within the carbon tube. Often the nonvisible cracks or delamination extend centimeters from the visibly damaged area.
Carbon fibre is hydroscopic (it absorbs water), and if the clear coat or gel coat on the frame has been damaged, the exposed carbon fibre will absorb water. Over time this will have a detrimental effect on the integrity of the frame as it causes the delamination of the carbon. It is imperative to inspect your frame and watch for scratches or cracks. If you suspect damage while inspecting your frame, contact your dealer or manufacturer as it may fall within the manufactures warranty.
On the left the image from a thermal camera shows a damaged frame. The right image shows a undamaged frame.
The left image of the damaged frame shows the visible damage in “red” (labeled #2). The bicycles carbon tube BVID damage that is nonvisible is shown in “yellow”. This nonvisible damage extends well past the visible areas of damage.
Things to be aware of:
- Handle carbon frames with care.
- Inspect your frame often.
- Do not sit on the top tube of the frame, as it is not designed to hold weight.
- If your frame has a visible crack, do not ride it! Contact your dealer or manufacturer.
- If your frame makes any noise such as creaks, groans, or cracks during riding, do not ride it! Contact your dealer or manufacturer.
- If your frame has a scratch and you can see bare carbon fibre, have it inspected by your dealer or manufacturer as soon as possible. Delaying the repair will lead to further damage.