A client had determined that in very dusty/dirty environments where their base-ported pressure filter is used, particles can get in between the threads of the tube and cap. The existing design uses standard fine pitch threads which are more easily damaged by dirt particles. Therefore, they designed a filter using coarser, more dirt tolerant, Acme threads. Since this is a new thread profile, they were concerned about potential fatigue life.
They asked O’Donnell Consulting to determine if Finite Element Analysis could be used to predict fatigue life of new designs in lieu of testing. An estimate of life for the tube threads based on strain-life methodology predicted 7.0E6 cycles.