Effect Of Parameter Of The Notch On Fatigue Life Of Shafts

For a long time, the notch parameter has been an important factor in the research of fatigue life. There have been rich experimental data accumulated and rather mature theories about the fatigue life of structure. However, in practical applications, there are many types of notch and materials and other factors. So it is impossible to form a unified design standard. So the specific research is formed for different material and for different notch under the specific conditions since the notch and type of special materials and other factors. In the process, describing the geometry parameters of the notch is one of important research.Based on fatigue design theory, this thesis will make depth study of the U-shaped incision in the gap parameters on the fatigue life of shaft for engineering application. Application of local stress-strain law, this thesis proposes the notch fatigue life calculation model. the incision depth and radius is analyzed in detail in the example of the U-shaped incision; the finite element analysis software Ansys11.0 was used to establish U-shaped incision shaft finite element model, and to study the U-notch parameters of the shaft of the high-quality carbon steel 45 for the law of the fatigue on the reverse loading condition.There are three main research areas:First, the thesis has analyzed the effect of parameter of the radius in U-shaped incision on fatigue life of shafts. Ansys11.0 was used to establish calculation model of fatigue life of shafts, in case of reverse loading, obtaining U-incision Von Mises equivalent stress-strain chart, through the local stress-strain law of fatigue life calculation formula, obtaining the fatigue life from the stress strain the incision. Concluding that and drawing out radius-fatigue life chart. And the result was took a reasonable analysis.Second, the thesis has analyzed the effect of parameter of the incision depth in U-shaped incision on fatigue life of shafts. The same design method is used to obtain the incision fatigue crack initiation life different depths and draw the chart of depth-the crack initiation life. Analyzing the effect of incision depth on fatigue life of shafts, the thesis derives reasonable conclusions.Third, comparing the notch parameters in different notches, and obtaining the general laws of the effect of parameter of the notch on fatigue life of shafts.