Based on Vibration Signal to Identify the Diesel Engine Modal Parameters under Working Condition

Abstract

Abstract The methods to study the dynamic characteristics of diesel engine structure include finite element analysis method and experimental analysis method. It is difficult to establish an accurate finite element model, since the results of finite element analysis methods are often not accurate. For the experimental analysis method, it is mainly divided into the traditional Experimental Modal Analysis (EMA) and the Operational Modal Analysis (OMA). The EMA method always needs to measure the excitation force of the diesel engine and the vibration response of the structure simultaneously. And the influence of motion factors on the structure dynamics cannot be considered. The structure is excitated by the working environment, and only analyzes the modal parameters of the structure with the vibration response. Few scholars analyze the OMA for diesel engines. This paper proposes a new method to identify the modal parameters of diesel engine based on self-excitation. In this paper, the theory of self-excitation mode parameter identification is demonstrated by derivation, and the validity of the method is verified.