Fatigue Rigs

Fatigue Spin Test Rigs are designed to expose rotating components to operating loads under realistic conditions. This enables rotor manufacturers to validate the predicted life (in numbers of cycles) of designated critical rotating components.

Test Devices’ Fatigue Rigs utilize the highest productivity drive systems in the industry. Our higher power drive systems are specifically designed for Low Cycle Fatigue (LCF) testing, enabling customers to “fast cycle” their test components. Fast cycling shortens program durations, cuts costs, and reduces the risk of damaging test assets.

Standard Modules

Data Acquisition: All test data (e.g., temperature, speed, vibration, strain) are recorded on a custom digital data acquisition system.

Containment Chamber: Industry leading containment capability designed for high energy applications.

Vacuum System: Includes the pump/blower set, providing a vacuum level below 400 milliTorr, together with controls and level gauge.

Cyclic Controller: Provides accurate control of speed for low cycle fatigue test protocols, including complex (mission profile) cycles. See Figure 1.

Drive Systems: Test Devices offers a range of drive options for both air turbine drive systems and direct electric motor drive systems, covering the speed range up to 160,000 rpm. Our 700 Series turbines are designed specifically to perform LCF tests very rapidly, providing good data faster.

Key Features

  1. Lid Lift
  2. Lid
  3. Lid Dog
  4. Cover
  5. Lead Brick Retainer Ledge
  6. Forged Steel Armor Liner
  7. Air Float Counterbalance
  8. Air Regulator
  9. Lead Brick Liner
  10. Casing
  11. Leveling Wedges

Armor Cylinder – Primary Containment

A robust armor cylinder is mandatory for long-term safety of the machine and the operator. The steel armor cylinder Test Devices uses for the primary containment of an uncontrolled burst is forged and heat treated. The single piece forging eliminates welds, reducing stress concentration and strength issues. It is designed to yield only under overload conditions, with an 18% elongation.

Test Devices designs armor cylinders to be fully elastic in both shear and tension, and they are reinforced at the top and bottom by a retention ledge. This feature strengthens the ends of the cylinder and prevents the extrusion of the soft lead inner liner against the covers.

Casing

The casing is fabricated from high strength steel. It encloses the entire test chamber and sustains a vacuum using airtight seals. The inside of the casing is larger than the outside diameter of the armor cylinder to allow the inner safety liner to expand if overloaded. This extra room allows the containment cylinder to stretch and absorb energy without ruining the vacuum chamber during an exceptionally high energy burst.

Options

 

Crack Detection

Test Devices offers a patented system that detects cracks in rotating assemblies and automatically shuts down a test before the test piece fails, saving the flawed component for analysis.
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Unattended Operation

Fatigue Rigs can be equipped with an optional module designed to run repetitively, up and down, at speed. This allows a test to run unattended, after business hours or over the weekend. If the test shuts down due to a crack, temperature limit, air supply issue, over-speed, or other defined condition, the system automatically.calls the test technician’s cell phone with a system code.

 

Spectrum Analyzer

The PC based spectrum analyzer is specially designed for spin rig application and allows the operator to monitor the vibration spectrum on-line from different locations in the spin chamber. The analyzer simultaneously displays the vibration spectrum and peak hold spectrum.

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Elevated Temperature

Isothermal Option

This option allows customers to test rotors at temperatures up to 1500° F (815° C), with special applications to 1600° F (871° C).

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Thermal Gradient

Constant Option

Thermal gradient capability enables customers to expose components to more realistic engine conditions, including the thermal gradient stresses which sometimes exceed centrifugal stress levels.
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Strain

Strain Measurement Option

This module enables customers to measure elastic and plastic growth of components in real time, at speed, verifying stress and growth models.

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Data Acquisition

All test data (e.g., temperature, speed, vibration, strain) are recorded on a custom digital data acquisition system.

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Radial Growth

Measurement Option

This module enables customers to measure elastic and plastic growth of components in real time, at speed, verifying stress and growth models.

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Tooling

Custom Spin Tooling

Many customers take advantage of Test Devices’ experience in manufacturing custom spin tooling and have the tooling delivered with the spin system.

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Video

High-Speed Video Option

Recording burst events with high-speed video equipment provides immediate data with regard to the component failure locations. Knowledge of the failure location can greatly simplify failure analysis.

Figure 2 - Normal spin, initial crack formation and test article bursting
Figure 2 – Normal spin, initial crack formation and test article bursting

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