A New Method For The Estimation Of Strain-life Curve Of Metals

Fatigue damage is a potential failure mode of metals,and it is always unexpected. Fatigue damagecauses serious harm to people’s lives and property. Therefor, the scientists pay more and more attentionto fatigue damage research.Fatigue phenomenon has great complexity, it relates to material science,mechanics, metal physics, applied mathematics and other disciplines. In the twenty century fifty yearsbefore, Metal fatigue research mainly focuses on the stress fatigue behaviour and has made much greatprogess; In recent decades, the strain fatigue has become the research foucs with the development ofthe test equipment.Strain fatigue analysis based on the material strain life curve,this article has made some researchon the method-Manson-Coffin equation which is the typical method of the strain life curves of themetal fatigue.The fatigue properties of Manson-coffin equation are strongly realting to the metalfatigue life prediction,the experimental method of getting the fatigue properties is cost much moneyand time,So,in order to achieve the fatigue properties,scientists have investigated the correlationsbetween single tensile properties and fatigue properties of Manson-coffin equation,in this study,firstgivng a summary of the methods of estimation the fatigue properties by the single tensile properties,Then,Proposing a simple model which based on only ultimate strength and modulus of elasticity, Thenew model is compared with other models which are common used. The new model is shown toprovide a better approximations of the fatigue properties of the strain-life curve.In this study,calculating the fatigue life of an engineer structure by using nominal stress methodfirst and then calculating the fatigue life by using the local stress-strain method,on this calculation ofthe local stress-strain method, the fatigue property has been gotten with the method of the new modelwhich proposed in the above study. The results show that the fatigue life of the structures arecomplying with the design requirements.while the new model is having a certain practical engineeringvalue...