Learning Forum

[peteroznewman]

Frank,

To model all the welds in a large assembly would take a lot of time. One approach to reduce the modeling time is to divide the analysis into a System model and one or more Detailed models. In the System model, you don’t need to model the welds, instead you insert a Joint between the hole in the lug and the strut connected to the lug for the purpose of extracting the forces and moments going into the lug. This is done for every lug in the System model. Probe the forces and moments of each joint and put the results into a spreadsheet. If the lugs are not all the same shape (and size), create a label for each unique shape and add a column in the spreadsheet to label each row with the lug shape. Sort the rows by lug labels and then by forces to find the largest force for each lug label.

Make a Detailed model for each unique lug shape. Apply the largest row of forces and moments for that lug shape to the Detailed model of that lug shape to evaluate whether it has positive stress margins for the largest forces and moments going into that lug shape. Repeat for each lug shape.

The benefit of this approach is you can use a coarse mesh on lugs without fillets in the System model because you are not looking at stress in the System model while the Detailed model uses a fine mesh on one lug with fillets to evaluate the stress.