Experimentally Based Statistical Forced Response Analysis for Purpose of Impeller Mistuning Identification

LectureA Root Cause Failure Analysis (RCFA) for repeated fourth stage impeller blade failures in a five stage centrifugal propane compressor used in Liquefied Natural Gas service is expanded upon by examining the amount and effect of impeller mistuning by using an intact fourth stage impeller taken from service. Mistuning refers to the fact that the blades of an impeller are not identical, but have slightly different frequencies. Mistuning can cause mode localization, higher vibratory stress, and reduced safety factors for high cycle fatigue. This paper describes both the experimental and analytical assessment of the effect of mistuning on the vibratory response of a fourth stage impeller taken from service