Officials from the University of Notre Dame Turbomachinery Laboratory (NDTL) (www.turbo.nd.edu), Norsk Titanium, Pratt & Whitney and Turbocam International are continuing the testing of an additively manufactured (AM) integrally bladed rotor (IBR).

Building on initial testing completed in 2018, this next phase of testing will examine the dynamic properties of the IBR.

Manufactured using Norsk’s Rapid Plasma Deposition (RPD) process (www.norsktitanium.com), it was inspected to the same quality specifications used in Pratt & Whitney’s current turbo-machinery components.

The tests are being conducted at NDTL’s turbo-machinery test facility in South Bend, Indiana.

After completion of the initial testing, where the IBR met all design, speed and pressure-ratio test points, the current test programme is looking at low- and high-cycle fatigue characteristics of the IBR.

Testing will include multiple acceleration /deceleration cycles and investigate synchronous vibration effects on the additively manufactured blades.

The testing was preceded by a manufacturing qualities evaluation performed by Turbocam. This found no evidence of ‘alpha case’ or residual stress concentrations that would cause the distortions typically found in additive materials.

Turbocam also confirmed that Norsk’s RPD material “was well suited to traditional milling operations, and was as stable as Ti6-4 forgings”.

Chet Fuller, Norsk’s chief commercial officer, said: “Successful completion of this testing will show that additive materials can be used in turbo-machinery applications, paving the way to a full qualification effort.”

Norsk is the world’s first FAA-approved OEM supplier of additively manufactured structural titanium components.

The company’s proprietary RPD process, which transforms titanium wire into complex components suitable for structural and safety-critical applications, has been in serial production of commercial OEM titanium components since April 2017.