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NDT inspections of Carbon Fiber Composite Components

By Valerio Marra 06 November 2019

Our Senior Application Engineer, Jeff Dobson will be attending NDT Aerospace 2019. The 3 day event will take place in Paris-Saclay, with over 200 participants expected to attend and over 100 technical presentations. Jeff will be presenting on improving ultrasonic inspection of tapered CFRP structure using cloud based FEA simulation. With the event just over a week away, we thought it would be the perfect time to share with you an interview with Jeff and our Director of Engineering, Cyprien Rusu discussing Non-Destructive Testing.

“The primary research of my doctorate was to look at using OnScale to simulate ultrasonic non-destructive testing inspections of carbon fiber composite components. I looked at creating accurate and efficient FEA models of these inspections scenarios so you could use them to evaluate and optimize your inspections. Non-Destructive Testing is essentially trying to look for defects or flaws in high integrity components. We’re trying to find cracks in various components to make sure they’re going to be safe and they’re not going to break or caused fatalities. So there’s a range of NDT techniques, the primary one I am looking at is using ultrasound. We are sending ultrasonic acoustic waves into the component which reflect off the sides of a component and defects so you can pick up these reflections and you can get a visual view of what’s inside your component.”

“Simulation is good because it’s cheaper and faster than going and doing lots of experiments. You can create simulations of various components and run different types of inspections so you can quickly and efficiently analyze and optimize your inspection without having to go and manufacture lots of tests pieces. It’s also very visual because your simulating what’s happening inside the component, you can actually see it. In experiment, all you’re going to see is the outside of the component and the reflection coming back and you don’t always know where these signals are coming from. Whereas with simulation, you can actually see what’s happening inside.”

“Composites are actually very tricky to both inspect with ultrasound but also to simulate and that’s because of their anisotropic material properties and also because they are very complex in their geometry. They are made up of very thin ply layers with even thinner resin layers between them and this causes reflection of the wave as it travels through. If you start changing the geometry of the component, such as tapers where we drop off plies and change the component thickness, this makes it even more complicated because you’ve got a lot more going on inside. You’ve also got woven fabrics where you have interwoven fibers, which again causes reflection and refraction of the beam as it goes through. These are all very difficult to inspect but also pose challenges to simulate because you’ve got complex geometry and varying material properties – there is a lot going on in these models.”

Check out the full video below to see an example of how simulation can aid these challenging NDT inspection scenarios.