ASR was contracted to determine the cause of a crack formation within a large welded aluminum reinforced vacuum chamber.
A crack formed within a large aluminum vacuum chamber near internal welds after an initial evacuation permitting leakage and preventing a vacuum from being obtained.
Analysis results indicated that extra supports were needed to reinforce the welded corners. Multiple design iterations were explored with a finite element shell model with a fully 3D sub-model of the worst-case rib corner. It was found that the support ribs were crushing the corners when the walls deflect inward under evacuation. Undercuts of the ribs at the corners were used to ease the compression on the weld.
Analysis results found that by undercutting the support ribs at the corners prevents the damaging compression at the heat affected zone of the weld.
- Through the use of finite element analysis (FEA), we were able to rapidly develop and test multiple design iterations to find an optimal engineering solution.
- An effective solution was found that could be implemented without permanent damage to the existing chamber.