A conditioning technique for projection-based reduced order models

Abstract

A conditioning technique for projection-based reduced order models (ROMs) in structural dynamics is presented together with examples of applications. Conditioning can be necessary especially when the projection vectors used to construct the ROMs are not guaranteed to be linearly independent numerically. This method is based on the reduced mass matrix, and it is particularly advantageous because all the conditioning is carried out in the ROM space. The computational effort and time required are thus substantially lower and with no accuracy loss compared to conditioning the entire transformation matrix in the full order space. An error metric is also introduced with the aim of helping the conditioning process. The method is tested using a simple example first, and then applied to the more complex case of ROMs for blended bladed disks (blisks). To evaluate the computational savings, the new method is directly compared to another state-of-the-art technique.