Find Evaluation Positions

The main objective of this function is to find the evaluation locations or positions for each of the 1D weld elements. The evaluation positions vary for each weld type.

Evaluation positions are determined based on the evaluation distance calculation specified by the weld regulations.

Note: In the classification area, if the evaluation distance method is set to manual, then the Evaldist value is used to find the evaluation positions.

The following inputs are required to determine the evaluation positions:

Evaluation distance
Weld width factor
Shell thickness
Direction vectors for the 1D elements

The calculations to arrive at the evaluations positions for the different types of welds are shown below.

For T and L Welds

Evaluation Distance: Evaldist = Standard distance from the specification
Weld Width: Weldwidth = Weld Width Factor * Shell Thickness
Evaluation Position from Weld Element Centroid: (Thickness / 2.0) + Evaldist + Weldwidth

For B and O Welds

Evaluation Distance: Evaldist = Standard distance from the specification
Weld Width: Weldwidth = Weld Width Factor * Shell Thickness
Evaluation Position from Weld Element Centroid: Evaldist + Weldwidth

Using this relative evaluation distance and the centroid data of the 1D element, the absolute coordinates of the evaluation positions are determined.

For each of these evaluation positions, the nearest shell element and the closest node of the shell element are determined. These entities will be used to get the stress results.

Evaluation Distance with 1 Point

Auto evaluation distance calculation
Example: T weld
Method: Auto

L₁ = (Shell Thickness / 2.0) + Evaldist 1 + Weldwidth

where,

Evaldist1: 1.5 * Min Shell Thickness
Weld Width: Weld Width Factor * Shell Thickness; Weld Width Factor (default) = 1
Stress: Stress is queried from Element at L₁

Note: For Manual Distance, L₁ is directly specified by the user.

Evaluation Distance with 2 Points

Auto evaluation distance calculation
Example: T weld
Method: Auto

L₁ = (Shell Thickness / 2.0) + Evaldist 1 + Weldwidth
L₂ = (Shell Thickness / 2.0) + Evaldist 2 + Weldwidth

where,

Evaldist 1: 0.5 * Min Shell Thickness
Evaldist 2: 1.5 * Min Shell Thickness
Weld Width: Weld Width Factor * Shell Thickness; Weld Width Factor (default) = 1
Extrapolated Stress: 1.5 (Stress at L₁) - 0.5 (Stress at L₂)
Stress at L₁: Stress is queried from Element at L₁
Stress at L₂: Stress is queried from Element at L₂

Note:

For Manual Distance, L₁ and L₂ is directly specified by the user.
When evaluating with element data, the stress is taken from the closest element centroid. This is not necessarily matching the exact evaluation distance.

Evaluation Distance with Corner Data

When evaluating with corner data, stress interpolation (method: Inverse distance weighting) is employed to average the stress from corner data of the element to the required evaluation point in both auto and manual methods.