Thermomechanical Fatigue (TMF)

Thermomechanical Fatigue (TMF) systems simulate the complex effects of simultaneous thermal and mechanical strain. This test is able to replicate the service conditions normally experienced by gas turbines, jet engines and the infrastructure associated with power generation.  More sophisticated than isothermal fatigue, TMF uses induction heating to achieve specimen heating rates in excess of 50°C/s. Instron’s dedicated TMF testing software is then able to extract the thermal strain and mechanical strain components from the total strain measured. 

TMF testing helps to better evaluate the life of materials and engineering components that are used in safety critical, high-temperature applications. The trend towards this testing is driven, among other things, by a growing requirement for power ‘on-demand’ or ‘reactive power’ that needs to work in conjunction with intermittent, renewable power sources.

Whilst the load string and heating technology are a crucial part of any TMF testing system, Instron also has two fundamentally different actuator technologies for you to consider. Most fatigue testing systems are hydraulically powered and deliver the high dynamic performance required to reduce the time taken to complete lengthy high cycle fatigue tests. In the case of TMF, testing is typically run at very slow speeds and precision strain control is more important that running at high frequencies.

As well as offering a traditional hydraulic technology for TMF, Instron offers a unique servo-electric actuator which is ideally suited to the challenges of TMF. Choosing Instron’s servo-electric technology will reduce the infrastructure requirements of your new machine and minimize your running costs. Whichever solution is best suited to your needs, Instron will supply a load frame with high lateral and axial stiffness and a precision alignment fixture to meet the demands of your TMF testing.

Instron acknowledge that the demands of TMF testing are very different to that of a ‘general purpose’ test machine and we design our software tools accordingly. Specialist TMF software makes it easy to carry out complex tests and get the results you need first time, every time; with automated calculations, real time data views and powerful post-processing built in.

Features

• High capacity loading frame maximizes lateral and axial stiffness during reverse stress testing.
• Optional backlash free, all-electric actuator delivers precise slow speed control with virtually silent operation and no hydraulic infrastructure requirements.
• AlignPRO alignment fixture and supporting software are provided as standard to ensure precision loadstring alignment.
• Multi-coil induction head allows more complex coil designs improving heating rates and specimen temperature gradients.
• Choice of internal or enclosed external cooling improves specimen cooling rates and reduces extensometer disturbances.
• Dedicated TMF software package is highly automated, minimizing the chance of human error and making complex testing more accessible.
• All Instron TMF systems are fully integrated and are supplied ready to test, meeting all appropriate international standards.

To find out more about Instron TMF systems, please click on the ‘Contact Us’ tab above and send us a message with your questions or requirements.