一、前言对于一个具体结构,要由已经得出的导纳矩阵返求出它的物理参数;质量、阻尼,刚度矩阵,这一问题即力学上的逆问题,亦称作系统识别问题。对于系统自由度与所测得的模态数相等的,称为完整模态系统识别。一般地说,系统的自由度往往多于所得到的模态数,这时称为非完整模型系统识别。对于模态为实模态的完整模型系统识别,一般并不困难,然而对于复模态的完整模型系统识别,文献上并不多见。702所陆圣才同志提出了一个公式,此公式稍嫌复杂,对于一个n维问题须占用2n~2的内存,并且计算的机时亦较多。本文提出一个计算公式,对于n维问题只占用n~2个 I. INTRODUCTION For a concrete structure, we must find out its physical parameters, mass, damping and stiffness matrix from the admittance matrix that has been derived. This problem is a mechanical inverse problem, also known as system identification problem. For the system degree of freedom equal to the measured modalities, it is called complete modal system identification. In general, the degree of freedom of the system is often more than the number of modalities obtained, then known as the non-complete model system identification. It is generally not difficult to identify the complete model system with modal real modalities, however, the complete model system recognition of complex modalities is rare in the literature. In the 702 Lu Comrade put forward a formula, this formula is a bit complicated, for an n-dimensional problems need to take 2n ~ 2 memory, and more computing time. This paper presents a formula that takes n ~ 2 for n-dimensional problems