Advanced Testing: Thermo-Mechanical Fatigue (TMF), Tension-Torsion and Bespoke Testing

 

The word fatigue means that the load and/or temperature can be fluctuating between defined levels. When this is the case, then thermo-mechanical fatigue is experienced by such components.  In this type of testing, the stress and the temperature are made variable between set values from which the fatigue life of components can be evaluated. The performance of the material can then be compared to normal fatigue conditions from which decision can be made on the level of safety of components. This scenario is observed in gas turbines as the stress varies between 0 (when the engine is switched off), maximum (when the engine is at highest speed), room temperature (when the engine is on the ground and switched off) and maximum temperature (when the engine is running). This application shows the influence of thermo-mechanical fatigue which might reduce the life of components and cause pre-mature failures.

On the other hand, the tension-torsion test allows the determination of the shear properties of materials. This capability allows the determination of properties that can not be obtained via uniaxial tensile testing alone. This test can be carried out at room and elevated temperatures. This type of testing allows the measurement of the torsional strength of materials under tensile loading conditions. In addition to the above, some Bespoke testing can be developed according the customer’s needs. In other words, non-standard testing can be developed using the existing machines where the machine can be developed in a way that provides the required outcomes that can no way obtained otherwise