基于传递路径分析方法的舰船耦合机械振源识别研究

The identification of mechanical noise sources and transfer paths of ship has become the bottleneck of the development of acoustic stealth of ship. Due to the complex and particular structure and working environment of ship, there are many sound sources with the characteristics of wide distribution and strong coupling. Therefore, the traditional methods which are used to identify noise sources and transfer paths of ship are often unsatisfactory. The transfer path analysis (TPA) method families, which have opened up a novel path for identifying dominant source sounds and transfer paths, are of great theoretical and practical significance. However, there are many problems to be solved when dealing with a complex structure of ship. Therefore, on the basis of the previous work, the transfer path analysis and its associated technologies are studied and improved deeply in this paper. .To improve the engineering practicability of the critical TPA, the two estimation models of FRF based on principal component analysis and total least squares were proposed, and moreover a novel matrix inverse method (MIM) for identifying load, regardless of the noise sources were removed or retained, was also proposed. Two iterative regularization methods in the TLS setting were proposed to solve the ill-posed problem of TPA methods. The operational transfer path analysis (OTPA) equation was also deduced to overcome the shortcomings of TPA algorithms in practical application. The critical issues of OTPA algorithms in practical application were firstly ascertained as follows: low coherence for good transmissibility estimates, cross-coupling between the path inputs, errors due to missing paths in the analysis. To deal with this critical those issues, many novel strategies were proposed and the corresponding OTPA algorithms were also established as follows: (a) Proposing the CSM-OPA algorithm by means of the complex stiffness method (CSM). (b) Proposing the SI-OPA algorithm on the basis of the system identification. (c) Proposing the JBD-OTPA algorithm based on a novel non-orthogonal joint block diagonalization (JBD) method. The TPA method system adapting to different the measurement conditions, structural objects, accuracy and efficiency was finally constructed. Combination of simulation analysis and the test of ship vibration and acoustic radiation in the water, the feasibility and correctness of the TPA method system which is used to identify noise sources and study the noise contribution were validated. The results indicate that those novel models can effectively identify and quantify noise source of ship which maintain the efficiency and also improve the accuracy. Therefore the new method established in this paper has broad prospect of engineering application.

舰船机械噪声源及其传播途径识别已成为舰船声隐身技术发展的瓶颈之一，传递路径分析（TPA）相关方法的提出为解决此问题开辟了新的途径，但实用中仍面临诸多现实问题。本项目将给出基于主成分和总体最小二乘法的频响函数估计方法，引入钳制力描述振源特性，给出不受振源存在或移除影响的逆矩阵法识别工作载荷，提高TPA方法的工程实用性；提出总体最小二乘正则化迭代算法，解决TPA相关方法中存在的不适定性问题；探明工况TPA方法面临的传递特性矩阵估计不准确、噪声源交叉耦合、遗漏传递路径无法检测等问题，并融合动刚度法、系统辨识思想、非正交联合块对角化方法，提出三种新的工况TPA模型。形成一套适用于舰船不同结构对象、工作环境、预期精度和效率的传递路径分析方法体系，并经过理论、实验室试验、海上试验验证该方法体系在舰船机械噪声源及其传递路径识别中既能保证分析精度和效率，又能充分利用现有的宝贵资源，理论和现实意义十分显著。

传递路径分析（TPA）相关方法在舰船机械噪声源及其传播途径识别中具有重要应用价值。为此，本项目基于主成分和总体最小二乘法的思想，分别提出SISO和MIMO测量条件下的FRF估计模型，并提出FRF测量环节合理实施的策略；提出不受振源存在或移除影响的逆矩阵法识别工作载荷，由此建立相应的TPA方法，并与现存方法进行比较,确定了TPA方法的计算精度、效率及适应范围。探明TPA中存在不适定性问题的病态特征，并提出迭代的Lanczos TTLS算法和共轭梯度迭代的TLS正则化算法有效解决TPA中存在的不适定性问题。开展舱段模型声振TPA仿真和试验，并验证TPA修正方法能成功实现水下舱段模型的振动源及其传递路径的量化、识别。针对TPA方法实际应用中的不足，推导工况传递路径分析（OTPA）方法，找出OTPA方法在实际应用中存在的关键问题：①传递特性矩阵估计不准确问题：提出优选参考测点和工况数组合的方法，构建出良态的矩阵，并结合新TLS正则化方法解决存在的不适定性问题。②忽略路径对整个贡献的影响：引入EMD-SVD源数估计方法和基于偏相干分析的重相干函数方法(PCA-MCF法)，实现振源输入测点的合理选择；③噪声源交叉耦合问题：基于动刚度法提出CSM-OPA模型；基于系统辨识思想提出SI-OPA模型；提出能消除幅值不确定性影响的BSS-OPA模型。开展船舶结构声振耦合仿真试验以及实船锚泊状态下的机械振源传递路径分析试验，并将融入新策略OPA模型成功用于船舶振动源及其传递路径识别。利用频谱贡献云图、路径贡献量柱状图、路径矢量图及数据对比的方式，实现振动源的贡献量准确排序、声场噪声有效预报，并由此判断出引起目标点响应的是船体结构还是振动噪声源的问题。本项目研究成果不仅可指导工程技术人员依据船舶不同的结构特点、设备布置、工作环境和预期目标等现状，选择最佳TPA（或OTPA）模型，也为控制船舶的噪声源水平和声学特征提供有力的支撑，进而为提高船舶的声隐身性能提供合理的指导。