Jet engine and gas turbine designers must understand the dynamic behavior of bladed rotors and devise a means to manage their resonant vibrations. The dynamic behavior of bladed rotor can be very complex and could result in incipient fatigue failures. The blade vibrations can be influenced by several variables, including its geometry, manufacturing tolerances, material, attachment and damping methods to name a few. The presence of foreign object damage and erosion can also significantly affect the fatigue durability and integrity of the blades. In some cases, a small change made during repair can cause unanticipated mechanical reactions.
Designing a robust bladed rotor system requires a careful understanding of the interaction between the various factors that influence the blade dynamic behavior and its structural integrity. Turbine blade failure is a serious safety issue that can be evaluated through Dynamic Spin Testing and High Cycle Fatigue testing.
Test Devices’ Solution
Test Devices, Inc. has developed and refined a unique approach to test and study the dynamic behavior of bladed rotors. Our Dynamic Spin™ Testing allows the testing of a fully assembled bladed disk. The spin test-based method combines the effect of centrifugal load with the vibratory excitation on the blades. The ability to test the full-size parts with the CF load simulates a realistic test condition, especially at the blade attachment area where the detail of the intricate geometry and the interactions of the parts have profound impact on the efficacy of the damping as well as the parts’ life.
Test Devices has developed proprietary blade excitation techniques and the technology to accurately control the rotational speed of a test rotor, enabling us to target specific resonant frequencies at different engine orders. With these technologies, Test Devices offers a means to establish what vibratory responses can be expected and study the damage mechanisms that affect the durability and the integrity of the parts.
What Is Dynamic Spin Rig?
Test Devices has pioneered the Dynamic Spin Rig (DSR) to accomplish practical, next-generation testing—a patented technology that has been developing since 2004.
The DSR is a spin test system that can simulate the realistic operational environment of a jet engine’s bladed rotors. Fully accounting for real-world conditions including the use of actual components, blade-rotor attachment mechanisms, damper systems, centrifugal loading and the relevant dynamic excitation load at a targeted engine order.
DSR is a useful tool for jet engine designers and engineers to study, measure data and validate:
- Blade resonance frequency & dynamic responses
- Campbell diagrams and FEA models
- Blade deflection and strain
- High Cycle Fatigue (HCF) life validation
- Wear damage/the efficiency of anti-friction coatings
- The effects of mistuning
- Blade resonance changes due to a crack or repair
Trusted Team in Dynamic Spin Testing
The safety and reliability of components that go into jet engines and gas turbine rotors are important to us at Test Devices. We offer our test solutions and engineering testing expertise to tackle even the most challenging requirements. To learn more about our processes and equipment, download our eBook, An Introduction to Dynamic Spin Testing, or contact us today.