In cyclic loading -also called fatigue loading- another equally important tool is required; the S/N diagram (Fig.2). This diagram identifies limiting stresses if a sensor were to survive a certain number of loading cycles without failure.

A favorable material for sensor manufacturers is the AISI 4340 alloy steel. Both Fig.1 & Fig.2 are for this alloy.  Fig. 2 also includes the behavior of A36 steel under cyclic loading.

From Fig.1, this alloy provides a useful linear design range for up to 1500 MPa. But if the sensor were to survive 100,000,000 cycles, the max stress it would be loaded to should not exceed 300 MPa from Fig. 2. Notice that for the same 300 MPa, A36 steel can only survive 30,000 loading cycles. In addition to showing why 4340 is a favorable material, this also shows emphatically why designing for general purpose and designing for fatigue, are completely two different processes.

Fatigue rated load cells are specifically designed for component durability and fatigue test machines where highly cyclical loading is present. …

All fatigue rated load cells are guaranteed against fatigue failure for 100 million fully reversed cycles.

They are used for material testing, component life cycle testing and structural testing. All fatigue rated load cells are guaranteed against fatigue failure for 100 million fully reversed cycles.

SDT has several field proven fatigue rated sensors, please refer to our website for some of those models.