Recommendation for selection of input force locations to improve blocked force determination on curved shells

Blocked force determination is increasingly being used as an alternative to the long-established approach of using transfer path analysis to determine inverse forces. In practice, the main difference between the two approaches is that the source does not need to be detached from the machine or receiver structure if blocked forces are determined. Moreover, blocked forces remain the same even if the receiver structure is modified. In this research, blocked forces are determined on curved shell structures along an interface which has been selected for measurement ease. Guidelines for numbers and placement of blocked forces are developed based on the bending wavelength using a simulation example. A measurement example follows where a small compressor is placed on a cylindrical drum structure and blocked forces are determined along an interface offset from the cylinder edge. Results are assessed by comparing the predicted and measured responses at a position which was not used for determining the blocked forces.