Patented Dynamic Spin™ Testing From Test Devices Inc. Enables Evaluation Of Static / Dynamic Stress Interaction For Blades In Turbine Engines

June 2, 2008

Test Devices Inc. (TDI), a dynamic materials testing company that provides state-of-the-art materials testing services and products, including its patented Dynamic Spin™ process for evaluating the performance of turbine engine blades and dampers, recently completed resonant spin tests on a series of first stage (R0) compressor blades for an F-Class industrial gas turbine. The tests were conducted for a major global energy services company in the process of developing a new, more efficient gas turbine blade design.

Test Devices Inc. is exhibiting at ASME Turbo Expo 2008 at the Estrel Hotel and Convention Center, Berlin, Germany, Booth 1111 (June 9 – 13, 2008). TDI will be providing information about these state-of-the-art resonant spin tests at its booth. In addition, Robert L. Murner, president of TDI, will give a presentation titled “Static and Dynamic (Goodman) Blade Characterization and Structural Performance Validation in a Rotating Environment” on Wednesday, June 11, 2008 from 5:30 – 6:15 p.m. at the Expo Stage at the Estrel Hotel and Convention Center.

In blade testing, it is of critical importance to consider both static (centrifugal) and dynamic (vibrational) stresses when evaluating blade performance and component life. Test Devices’ patented oil jet excitation system has demonstrated the capability to produce resonant vibratory amplitudes sufficient to initiate cracks from ceded flaws.

Robert L. Murner, President of Test Devices, Inc., stated, “evaluating the interaction of static and dynamic stresses (essentially, Goodman diagram validation) requires precise speed control, especially for poorly damped modes, and enough force at the appropriate engine order to hit the Goodman line and hold for 10 million cycles. We recently accomplished these tests for a series of very large stiff blades from an industrial gas turbine.”

Test Devices Inc. worked very closely with the customer to define the application, fabricate the tooling and excitation system, and deliver results in a very short time period so that critical component data was available for a scheduled field test. During spin testing, multiple modes were excited in order to validate critical blade responses. Dwell periods were between three and four hours in duration and required extremely tight speed control in order to stay on resonance for these poorly damped modes.


About Test Devices
For over 30 years, Test Devices, Inc. has been the world’s premier source for rotational testing equipment and services. Test Devices provides advanced technology spin testing services to customers in a wide variety of industries. The company works with developers and producers of high-speed rotational components of jet engines, gas turbines, medical centrifuges, machine tools, industrial compressors, and high-speed electric motors, among others. For more information contact David Woodford at +1-978-562-4923,, or visit