输入未知情况下结构复合反演的两步法

研究了输入未知条件下的参数识别问题。针对剪切型结构,提出了其在一类特殊未知载荷下的复合反演算法,此方法假设结构各层上的未知输入之间成比例关系,在不知道这些比例关系的情况下,分两步进行复合反演:第一步,假设某一层上的未知输入为基本未知输入,利用子结构技术,采用遗传算法识别子结构参数和子结构上未知输入之间的比例关系,进而求出基本未知输入;第二步,在基本未知输入已知的情况下,通过最小二乘算法识别其余各层的未知参数和其余各层上未知输入与基本未知输入之间的比例关系。此方法在类似风荷载作用未知情况下的复合反演中具有重要意义,最后用剪切型数值算例验证了算法的合理性。

A Two-stage Method for System Identification in Unknown Input Case

In this paper, structural system identification without input information is studied. To shear-typed building under a special kind of unknown input, a new method is proposed to inverse load process and estimate structural parameters. In this method, the unknown inputs acting on different floors are supposed to be proportional and the computing process can be divided into two steps. By defining a basal unknown input, this problem is changed to obtain the basal unknown input, the structural parameters and the proportion coefficients of the rest unknown inputs relative to basal unknown input. In the first step, a two-floor sub-structure including the basal unknown input is used, applying Genetic Algorithm, the unknown parameters of the sub-structure, the basal unknown input and one proportion coefficient can be solved respectively. In the second step, using the basal unknown input obtained before, the least-square method is applied to solve the inversion problem of the rest unknown structural parameters and the rest proportion coefficients of the whole structure. Due to not needing the proportional coefficients beforehand, this method have a wide range of application background. At last, a numerical example is used and the results show that this method can effectively identify the structural parameters and the unknown inputs.