Fatigue curves of a low carbon steel obtained from vibration experiments with an electrodynamic shaker

Highlights: • Accelerated vibrational fatigue-testing methodology using electrodynamic shaker • Establishment of the high-cycle fatigue curves • Failure criteria defined from the reduction of the strain slope are used. • Comparison of the failure criteria with modal parameter changes - Abstract: This paper presents an original contribution for the establishment of the high-cycle fatigue curves ε–N_f (strain versus cycle number to failure) of low carbon steel under vibratory testing. These curves are obtained thanks to a vibrational fatigue bench composed of an electrodynamic shaker and a closed loop vibration control system. The main advantage of this is the high frequency excitation compared to conventional fatigue systems. Three criteria based on strain gauge measurements are implemented to provide cycle numbers to failure N_f and to plot the fatigue curves. Furthermore, cycle numbers to failure are also assessed from two modal parameters (resonant frequency and loss damping factor) and compared with the results obtained from these three criteria. Some micrographies of fractured samples observed by scanning electron microscope reveal fatigue striations but also intergranular fracture.