fatigue
Machine Design II
Prof. K.Gopinath & Prof. M.M.Mayuram
FATIGUE CONSIDERATION IN DESIGN
OBJECTIVES AND SCOPE
In this module we will be discussing on design aspects related to fatigue failure, an important mode of failure in engineering components. Fatigue failure results mainly due to variable loading or more precisely due to cyclic variations in the applied loading or induced stresses So starting from the basic concepts of variable (non-static) loading, we will be discussing in detail how it leads to fatigue failure in components, what factors influence them, how to account them and finally how to design parts or components to resist failure by fatigue WHAT IS FATIGUE?
Fatigue is a phenomenon associated with variable loading or more precisely to cyclic stressing or straining of a material. Just as we human beings get fatigue when a specific task is repeatedly performed, in a similar manner metallic components subjected to variable loading get fatigue, which leads to their premature failure under specific conditions.
WHAT IS FATIGUE LOADING?
Fatigue loading is primarily the type of loading which causes cyclic variations in the applied
stress or strain on a component. Thus any variable loading is
basically a fatigue loading.
Indian Institute of Technology Madras
Machine Design II
Prof. K.Gopinath & Prof. M.M.Mayuram
Variable Loading
Variable loading results when the applied load or the induced stress on a component is not constant but changes with time i.e load or stress varies with time in some pattern. Most mechanical systems and devices consists moving or rotating components. When they are subjected to external loadings, the induced stresses are not constant even if the magnitude of the applied load remains invariant. In reality most mechanical components experience variable loading due to
-Change in the magnitude of applied load Example: punching or shearing operations-Change in direction of load application
Prof. K.Gopinath & Prof. M.M.Mayuram
FATIGUE CONSIDERATION IN DESIGN
OBJECTIVES AND SCOPE
In this module we will be discussing on design aspects related to fatigue failure, an important mode of failure in engineering components. Fatigue failure results mainly due to variable loading or more precisely due to cyclic variations in the applied loading or induced stresses So starting from the basic concepts of variable (non-static) loading, we will be discussing in detail how it leads to fatigue failure in components, what factors influence them, how to account them and finally how to design parts or components to resist failure by fatigue WHAT IS FATIGUE?
Fatigue is a phenomenon associated with variable loading or more precisely to cyclic stressing or straining of a material. Just as we human beings get fatigue when a specific task is repeatedly performed, in a similar manner metallic components subjected to variable loading get fatigue, which leads to their premature failure under specific conditions.
WHAT IS FATIGUE LOADING?
Fatigue loading is primarily the type of loading which causes cyclic variations in the applied
stress or strain on a component. Thus any variable loading is
basically a fatigue loading.
Indian Institute of Technology Madras
Machine Design II
Prof. K.Gopinath & Prof. M.M.Mayuram
Variable Loading
Variable loading results when the applied load or the induced stress on a component is not constant but changes with time i.e load or stress varies with time in some pattern. Most mechanical systems and devices consists moving or rotating components. When they are subjected to external loadings, the induced stresses are not constant even if the magnitude of the applied load remains invariant. In reality most mechanical components experience variable loading due to
-Change in the magnitude of applied load Example: punching or shearing operations-Change in direction of load application