Mean-stress sensitivity of an ultrahigh-strength steel under uniaxial and torsional high and very high cycle fatigue loading.

The influence of load ratio on the high and very high cycle fatigue (VHCF) strength of Ck45M steel processed by thermomechanical rolling integrated direct quenching was investigated. Ultrasonic fatigue tests were performed under uniaxial and torsional loading at load ratios of  = -1, 0.05, 0.

Ultrasonic fatigue testing of concrete.

Cyclic compression fatigue properties of concrete are studied with the ultrasonic fatigue testing method with cycling frequency 19 kHz and are compared to servo-hydraulic tests performed at 60 Hz. Ultrasonic testing was found applicable for rapid generation of very high cycle fatigue (VHCF) data of concrete. Fatigue cracks can be initiated, however specimens do not rupture, since cyclic stresses decrease with increase of compliance in displacement controlled ultrasonic tests.