Image made using the COMSOL Multiphysics® software and is provided courtesy of COMSOL.
Low-cycle fatigue resulting from plastic deformation near a hole showing the logarithm of lifetime in terms of number of cycles together with a stress-strain curve for the first few load cycles.
When structures are subjected to repeated loading and unloading due to material fatigue, they can fail at loads below the static limit. A virtual fatigue analysis can be performed in the COMSOL Multiphysics environment with the Fatigue Module, an add-on to the Structural Mechanics Module, which contains a collection of fatigue models. The applicability of each model depends on factors such as material and loading type.
The classical stress- and strain-life methods relate a stress or strain amplitude to a fatigue lifetime. Together with the stress-based and the strain-based critical plane methods, you can evaluate the high-cycle and low-cycle fatigue regime. In applications involving nonlinear materials, you can use energy-based methods or Coffin-Manson type models to simulate thermal fatigue. When dealing with variable loads, the accumulated damage can be calculated from the load history and the fatigue limit.
The fatigue load cycle can be simulated in solid bodies, plates, shells, multibodies, applications involving thermal stress and deformation, and even on piezoelectric devices. In order to improve computational efficiency when dealing with subsurface or surface initiated fatigue, a fatigue evaluation can be performed on domains, boundaries, lines, and in points.