What is multiaxial state of stress?
Multiaxial stress states due to the action of various external loads exist at the considered point of the machine or structure. In the proposed algorithm the multiaxial stress states history is reduced to an uniaxial equivalent one by a maximum shear and normal stresses criterion (1).
What is equivalent stress in fatigue?
An equivalent stress has nothing to do with fatigue, it is merely a calculation number to estimate the onset of yielding on macro scale in a multiaxial stress situation. Often for shear a factor of (1/3)√3 is applied on the fatigue strength for tensional fatigue.
What are the 3 methods in fatigue analysis?
There are three well established methods for calculating fatigue; Stress Life, Strain Life, and Linear Elastic Fracture Mechanics.
What is meant by equivalent stress?
The damage-equivalent stress is defined similarly to the plastic von Mises-equivalent stress for plasticity as the one-dimensional stress σ* which, for the same value of the damage, yields the same value of the elastic strain energy density as in the case of a three-dimensional state.
What is von Mises stress theory?
The von Mises yield criterion states that if the von Mises stress of a material under load is equal or greater than the yield limit of the same material under simple tension then the material will yield.
What is the fatigue method?
Fatigue analysis itself usually refers to one of two methodologies: either the Stress-Life (S-N) or S-N method, commonly referred to as Total Life since it makes no distinction between initiating or growing a crack, or the Local Strain or Strain-Life (e-N) method, commonly referred to as the Crack Initiation method …
Why is equivalent stress needed?
Equivalent stress is widely used to represent a material’s status for ductile material. Engineers use this simple scalar value to determine if the material has yield or failed.