Review on the Application of the Nonlinear Output Frequency Response Functions to Mechanical Fault Diagnosis

Abstract

Key components of mechanical equipment are prone to defects or failures during operation, resulting in equipment performance degradation because of harsh working environments and abnormal working conditions. The faults may induce the mechanical structures to behave nonlinearity. Some linear methods cannot accurately describe systems’ nonlinear characteristics. Nonlinear output frequency response functions (NOFRFs) well reveal the generation mechanism of nonlinear phenomena. The main objective of this article is to summarize the development and state-of-the-art research of NOFRFs in mechanical fault diagnosis. The method of NOFRFs is briefly introduced. Associated indexes of NOFRFs are summarized and two case analyses on the performances of associated indexes are conducted. Recent applications of NOFRFs in mechanical fault diagnosis are analyzed from the following aspects: 1) direct diagnosis of NOFRFs; 2) diagnosis of NOFRFs-associated indexes; and 3) NOFRFs+ diagnosis. Finally, the limitation of NOFRFs in fault diagnosis is pointed out and future directions are given.