弹性薄板结构的等效激励谱反演问题研究

摘要

Detection of sonar platform excitations has been a formidable obstacle towards the estimation and evaluation of mechanical self-noise in the sonar cavity.In view of the complexity oftransmission of excitations from mechanical vibration equipment to a sonar platform,an inversion technique,i.e.,indirectly estimating the outside excitations by means of measurement of vibratory responses,would be the most applicable and feasible.An equivalent excitation method is proposed in this paper,based on the hypothesis that responses resulted from equivalent excitations would be equal to those from the actual excitations,to deal with the inverse excitation problem in situations where there is no knowledge about the location and distribution of dynamic excitation forces acting on structures.Influential factors in estimation of equivalent excitations are carefully analysed based on modal theory of panel structures,with both analytical analysis and FEM simulation method.It could be concluded that the equivalent excitation inversion would be a practical method for evaluation of environmental excitations.%在声纳基阵腔内机械自噪声预报问题的研究中,确定平台区激励一直是个难题,考虑振源设备激励向声纳部位传播过程的复杂性,通过测量平台区振动响应对其外部激励情况进行估算是最具可行性的一种方法.本文根据弹性薄板结构的振动模态理论和简支边矩形薄板的Navier解法,详细探讨了在外部激励的分布状态未知或难以确定的情况下,基于响应相似原则进行等效激励虚拟假设,利用实测板壳结构振动响应和模态参数对等效激励进行反演计算的一般原理方法,分别用解析法和有限元法对等效激励估计实验方案中影响结果可靠性的主要因素进行了分析论证.结果表明,等效激励法是一种适用于激励作用位置缺失情况下,可靠的便于工程应用的环境激励反演评估方法.