柴油机油底壳动态特性识别研究

Research on dynamic characteristics identification of diesel oil pan

以某型单缸柴油机油底壳为研究对象,融合同步压缩小波变换法、1/3倍频程谱法及模态分析法的优势,识别其结构动态特性。首先,在标定工况下选用同步压缩小波变换法提取油底壳振动响应的时频特征,结合近场声压1/3倍频程谱法分析油底壳噪声的辐射特性,获得油底壳结构动态响应与其辐射噪声的关联特性;然后,基于试验与仿真相结合的模态分析法识别油底壳的模态特性,确定导致油底壳结构声振特性变差的薄弱环节;最后,采取加强筋改进设计措施提高薄弱结构刚度,优化结构动态特性。仿真计算结果可指导控制油底壳结构的声振特性。

Taking a single cylinder diesel engine oil pan as the research object,the structural dynamic characteristics are identified by combining the advantages of synchronous compression wavelet transform,1/3 octave spectrum method and modal analysis method.Firstly,the time-frequency characteristics of the vibration response of the oil pan are extracted by using the synchronous compression wavelet transform method under the calibration condition.Then,the noise radiation characteristics of the oil pan are analyzed by combining the near-field sound pressure 1/3 octave spectrum method,and the correlation characteristics between the dynamic response of the oil pan structure and the radiation noise are obtained.On this basis,the modal characteristics of the oil pan are identified based on the modal analysis method combined with the test and simulation,and the weak links that lead to the deterioration of the acoustic and vibration characteristics of the oil pan structure are found.Finally,the stiffness of the weak structure is improved by adopting the measure of reinforcement improvement design,the dynamic characteristics of the structure are optimized.The simulation results guide the later control of the acoustic and vibration characteristics of the oil pan structure.