Vibration and Shock FEA Analysis of Shipboard Heat Exchanger to Engineering Codes

(FEA) Vibration, Shock and Lifting Load Analysis was Performed on a Shipboard Heat Exchanger to Determine if it meets Engineering Codes including ASME.

Because the heat exchangers are shipboard equipment, the American Bureau of Ships (ABS) requires that they be analyzed for stresses caused by motion loads. The unit was specified to maintain vibration conditions for frequencies up to 50 Hertz. A modal analysis was conducted to identify natural frequencies under 50 Hertz, and to confirm there were no frequencies in the range of 0 to 33 Hertz – with the exception of rigid body movement of the unit on the vibration isolation springs. The results of the modal analysis revealed seven natural frequencies below 33 Hertz.

Static shock loading was performed using the following assumptions:

1) Isotropic, linear elastic material behavior – assumed with small displacement theory
2) Stresses in the vibration spring isolators are acceptable for the applied loads

The finite element model was subjected to a vertical shock load of 18.5g and horizontal shock loads of 5.1g. These loads were applied independently of each other. The maximum stresses in all of the unit’s structural components and fasteners were found below the allowable stress limits. After all of the analyses were performed, it was determined that the heat exchanger satisfactorily withstands the design vibration, shock, transportation, and lifting loads.

O’Donnell Consulting Engineers Performs Design and (Thermal, Stress, Vibration and Shock) Analysis of Equipment to Codes including AWS, API and ASME.