Cyclic Creep Strain Research Articles

Effects of the Change of the Maximum Stress and the Stress Ratio on the Cyclic Creep Behaviors

Cyclic creep behaviors of carbon steel are investigated by the true stress controlled low-cycle fatigue tests, stepwise or linearly increasing or decreasing maximum stress with a changing stress ratio. The constitutive equation proposed previously by the authors is found to be applicable to represent the strain accumulations in both increasing and decreasing stress conditions. The shape of the hysteresis loop including the cyclic creep strain increment is also discussed.

Application of equivalent stresses in calculating cyclic creep strains

Cyclic creep has been studied in some detail under conditions of slowly changing loads [3-5 and others]. Material creep under cyclic loading with frequency f corresponding to normal ( f = 15-90 Hz) and high (f = 300-10,000 Hz) frequency loading conditions have not been studied sufficiently [2]. However, these loading schedules are typical for the majority of materials used in gas turbines, compressors, and other critical assemblies of modern machines.

An approach to the determination of cyclic creep strain

Cyclic creep strain is often observed in power equipment parts, especially in gas-turbine rotor blades subjected to the complex action of static and alternating loads over a wide frequency range at high temperature [1-5]. Since the cyclic component of the load has a marked effect on creep rate, and consequently on the endurance of the part and the whole strucure [2-4], considerable attention is de ~ted to studying this process,

CYCLIC INDUCED CREEP OF A PLAIN CARBON STEEL AT ROOM TEMPERATURE

Abstract— Plain carbon steel specimens subjected to cyclic and superimposed mean stresses show significant plastic strain at intermediate life due to cyclic creep deformation at room temperature. Cyclic creep strains can also be observed in the high cycle region with Nf > 2. 106. An extended Haigh‐diagram provides information about the resulting mean strain at predetermined cycles.