Additively manufactured integrally bladed rotor enters second phase of testing

PARIS—Officials with the University of Notre Dame Turbomachinery Laboratory (NDTL), Norsk Titanium, Pratt & Whitney, and TURBOCAM International have announced the continuation of testing of an additively manufactured integrally bladed rotor (IBR).

Building on initial testing that was completed in 2018, this next phase of testing examines the dynamic properties of the IBR. Manufactured using Norsk’s Rapid Plasma Deposition™ (RPD™) process, the IBR was inspected to the same quality specifications used in Pratt & Whitney’s current turbomachinery components.

The tests are being conducted at NDTL’s turbomachinery test facility in South Bend, Indiana. Following completion of the initial testing, where the IBR reportedly met all design, speed, and pressure ratio test points, the current test program looks at low and high cycle fatigue characteristics of the IBR. Testing will include multiple acceleration and deceleration cycles and investigate synchronous vibration effects on the additively manufactured blades.

The testing was preceded by a manufacturing qualities evaluation performed by TURBOCAM (www.turbocam.com). The evaluation is reported to have found no evidence of alpha case, or residual stress concentrations, that would cause distortions typically found in additive materials. TURBOCAM confirmed that Norsk’s RPD™ material was well-suited to traditional milling operations and was as stable as Ti6-4 forgings.

The goal of the effort is to develop the manufacturing specifications needed to deliver the complex, heavily loaded components for turbomachinery applications, while providing the cost and schedule savings that have been proven on Ti 6-4 airframe components.

“Successful completion of this testing will show that additive materials can be used in turbomachinery applications, and paves the way to a full qualification effort,” said Norsk Chief Commercial Officer Chet Fuller, in a press release.

The entire manufacturing and testing effort has been overseen by Pratt & Whitney and is being evaluated for application to future engine developments.

“Pratt & Whitney is excited to enter this next phase of testing,” said Chris Kmetz, vice president of engineering, Module Centers, Pratt & Whitney. “Utilizing additive manufacturing techniques, such as Norsk’s Rapid Plasma Deposition process, allows us to shorten the manufacturing and development schedule for our critical turbomachinery components.”

Norsk Titanium (www.norsktitanium.com), a tier-1 supplier to Boeing, developed a patented Rapid Plasma Deposition™ (RPD™) process that is reported to transform titanium wire into complex components suitable for structural and safety-critical applications. The process is said to produce the world’s first FAA-approved, 3D-printed, structural titanium.

The Notre Dame Turbomachinery Laboratory (NDTL) is a gas turbine research and development facility supporting major OEMs in the aerospace propulsion and power industries. The laboratory (turbo.nd.edu) works on the leading edge of component aerodynamics, structural dynamics, instrumentation, and computational methods.

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