Critical plane analysis

Critical plane analysis is widely used in engineering to account for the effects of cyclic, multiaxial load histories on the fatigue life of materials and structures.

For the general 3D case, the orientation may be specified via a unit normal vector of the plane, and the associated stresses strains may be computed via a tensor coordinate transformation law.

The chief advantage of critical plane analysis over earlier approaches like Sines rule, or like correlation against maximum principal stress or strain energy density, is the ability to account for damage on specific material planes.

This means that cases involving multiple out-of-phase load inputs, or crack closure can be treated with high accuracy.

Additionally, critical plane analysis offers the flexibility to adapt to a wide range of materials.