What is Finite Element Analysis (FEA)?
Finite Element Analysis (FEA) is used to solve engineering problems that are too complex to be handled using the traditional mathematically closed form solutions.
According to my course notes from university: "the finite element method is a numerical method used to find an approximate solution for such complicated problems which involve irregular domains and difficult boundary and load conditions." In broad terms, a static analysis involves breaking the complex structure down into simpler elements, which are then solved as part of the whole. Stresses and displacements are some of the outputs based on applied loads and boundary conditions.
For CRN applications, the Finite Element method can be used when the component falls outside of the Code's standard configurations. UG101(b), for determining MAWP using proof tests, gives guidelines that can be generally used to determine when an FEA would be permitted:
"The tests in these paragraphs may be used only for the purpose of establishing the maximum allowable working pressure of those elements or component parts for which the thickness cannot be determined by means of the design rules given in this Division."
ASME VIII1, 2007 Ed, 2008 Add, UG101(b)
1.

Joint Orientation: The eccentrically attached weld allows the joint to open under pressure.

2.

Fatigue Life: The peak stress created at the weld root limits the fatigue life.

3.

Weld size: The weld size is insufficient to satisfy the Code’s geometric requirements
