The Experimental Study and Constitutive Description on Cyclic Creep/Relax Behavior of Magnesium Alloy;

In order to quantitatively describe the damage of interaction between fatigue and cyclic creep,a new damage parameter considered stress rate and elasticity modulus rate was proposed to define the damage variable.

In order to quantitatively describe the damage of interaction between fatigue and cyclic creep,a new damage parameter named equivalent modulus was proposed to define the damage variable,and a continuum damage mechanics(CDM) model considering both effects of maximum stress and temperature on damage evolution was put forward.

By applying different amounts of strain along with the welding ther-mal cycle simulation, the time of fracture and the creep ductility were measured by the short-time creep test so as to estimate the tendency of the welding reheat cracking.

According to main factors of affecting low cycle fatigue(LCF) life for gas turbine blade of single crystal nickel-based superalloy,the formula and computing method of cyclic plastic strain energy were studied and discussed.

It is a long time since the cyclic plastic strain energy was used as fatigue variability to study fatigue failure,but it is still lack of mathematical expression about cyclic plastic strain energy evolutional rule.

In this paper, the cyclic plastic strain energy is acted as damage variable and its mathematical model of transient response is established.