基于模态分析的发动机表面振动预测分析

Prediction and Analysis of Engine Surface Vibration Based on Modal Analysis

以某发动机动力总成为对象,采用多参考点最小二乘复频域法,通过模态试验测得振动响应,以获得发动机模态参数及振型。同时采用有限元-多体动力学-边界元相结合的方法,对其声场和表面振动速度进行预测。结果表明:该发动机前四阶模态主要以弯曲和绕X轴一阶扭转为主,发动机辐射噪声能量及表面振动主要集中在进、排气侧,频带为450~650Hz。研究结果为发动机设计改进提供依据,对发动机设计具有较强的实用价值。

Taking a certain engine powertrain as the object,using the multi-reference point least squares complex frequency domain method,the vibration response is measured through modal tests to obtain engine modal parameters and vibration shapes.At the same time,the combination of finite element-multibody dynamics-boundary element method is used to predict the sound field and surface vibration velocity.The results show that the first four modes of the engine are mainly bending and first-order torsion around the X axis,and the engine radiated noise energy and surface vibration are mainly concentrated on the intake and exhaust sides,with a frequency band of 450 Hz to 650 Hz.The research results provide a basis for the improvement of engine design and have strong practical value for engine design.