Several new calculating equations on the damage-evolving rate are suggested for describing the elastic-plastic behavior of some materials under un-symmetric cyclic loading. And the estimating formulas are given of th...Several new calculating equations on the damage-evolving rate are suggested for describing the elastic-plastic behavior of some materials under un-symmetric cyclic loading. And the estimating formulas are given of the life relative to varied damage value D oi at each loading history. The method is to adopt the ratio of plastic strain range to elastic strain range as the stress-strain parameter, using the staple material constants as the material parameters in damage calculating expression. And it gives out a new concept of the compositive material constant, that has a functional relation with the staple material constants, average stress,average strain and critical loading time. In addition, it calculates fatigue damage as example for a part of car, its calculating results are accordant with the Landgraf’s equation, and calculating precision is more rigorous, so could avoid unnecessary fatigue tests and will be of practical significance to stint times, manpower and capitals, and to provide convenience for engineering applications.展开更多
Suggests some calculating formulas and methods with respect to the damage evolvingrate da / dN|i and the fatigue life and in varied history from uncrack to microcrackinitiation until fracture for a crankshaft, which ...Suggests some calculating formulas and methods with respect to the damage evolvingrate da / dN|i and the fatigue life and in varied history from uncrack to microcrackinitiation until fracture for a crankshaft, which are suitable to stress concentration positionsabout its journal fillets and oil holes on a crankshaft, that it is undergone to bending, twistingand shearing loading and subjected to unsymmetric cyclic many-stage loading. Last the total lifein whole process is estimated by展开更多
文摘Several new calculating equations on the damage-evolving rate are suggested for describing the elastic-plastic behavior of some materials under un-symmetric cyclic loading. And the estimating formulas are given of the life relative to varied damage value D oi at each loading history. The method is to adopt the ratio of plastic strain range to elastic strain range as the stress-strain parameter, using the staple material constants as the material parameters in damage calculating expression. And it gives out a new concept of the compositive material constant, that has a functional relation with the staple material constants, average stress,average strain and critical loading time. In addition, it calculates fatigue damage as example for a part of car, its calculating results are accordant with the Landgraf’s equation, and calculating precision is more rigorous, so could avoid unnecessary fatigue tests and will be of practical significance to stint times, manpower and capitals, and to provide convenience for engineering applications.
文摘Suggests some calculating formulas and methods with respect to the damage evolvingrate da / dN|i and the fatigue life and in varied history from uncrack to microcrackinitiation until fracture for a crankshaft, which are suitable to stress concentration positionsabout its journal fillets and oil holes on a crankshaft, that it is undergone to bending, twistingand shearing loading and subjected to unsymmetric cyclic many-stage loading. Last the total lifein whole process is estimated by
