基于有限元与多体动力学仿真发动机失火故障特征提取研究

摘要

提出基于多体动力学和有限元计算的故障仿真方法,通过分析比较振动信号变化来提取故障特征.利用AVL EXCITE平台,建立一个高质量带悬置的四缸发动机动力总成有限元多体动力学仿真模型,以发动机失火故障为例,设置相关参数模拟失火状态运行,求解发动机稳态转速和加速工况的缸体和缸盖位置振动加速度响应信号,经频谱、阶次和小波等分析,对比正常状态和故障状态的差异,提取故障特征.通过实车失火故障试验进行对比,发现仿真结果与试验结果有较好的一致性.利用多体动力学有限元模型进行故障仿真分析的结果,可用于指导实际发动机故障诊断.%A fault simulation method based on multi-body dynamics and finite element calculation was proposed, and fault features were extracted by means of analysis and comparison of vibration signals. In AVL EXCITE platform, a high quality finite element and multi-body dynamics model of four-cylinder engine with mounts was designed. Taking misfire fault as example, vibration signals of engine block or head were gained under steady and acceleration operating conditions by setting related parameter for simulation. By virtue of spectrum, order, and wavelet analysis, differences between normal and fault state were extracted as fault features. It can be found that the simulation result is consistent with the experimental result, therefore, fault simulation and feature extraction by using the multi-body dynamics and finite element model can guide the engine fault diagnosis.