改进模拟退火算法的喷管动力学模型修正

为获得液体火箭发动机喷管高精度的结构动力学有限元模型，提出一种基于改进模拟退火算法（Improved Simulation Annealing Algorithm，ISAA）的有限元模型修正方法。首先，将复杂的薄壁夹层板喷管等效为复合材料层合壳，建立喷管的参数化有限元模型；在此基础上，以结构模态参数为参考基，构造出联合使用模态频率及模态振型的目标函数，并运用灵敏度分析提取设计变量，从而建立其优化模型；提出带记忆、局部搜索功能的改进模拟退火算法，运用ISAA在设计空间进行多目标全局寻优；最后，采用基于MSC Patran/Nastran软件平台二次开发的结构动力学模型修正软件ZDXZ V1.0进行模型修正，并对模型修正方法的有效性进行了校验。结果表明，修正后喷管的前3阶计算模态频率与试验值相对误差小于2%，振型相关性最小MAC值大于0.9，大大提升了喷管模型的动力学符合性，模型精度满足工程应用要求；表明所述模型修正策略的有效性，该方法具有高效、强鲁棒性等特点，适合于大型复杂结构的模型修正。

A Dynamics Model Updating Method of Nozzle Based on Improved Simulation Annealing Algorithm

 To obtain the high-precision structural dynamics FE (Finite Element) model of a liquid rocket engine nozzle, a method for updating the FE model is proposed based on the improved simulated annealing algorithm (ISAA). First, a parametric FE model of the nozzle is established, in which the nozzle is modeled as a laminated composite shell. The structural modal parameters are treated as the reference base, followed by constructing the objective function using the combined modal frequencies and shapes. The design variables are extracted utilizing the sensitivity analysis. Based on the above ideas, the optimization model is established. Then, the ISAA with the functions of memory and local-searching is proposed and applied to the multi-objective global optimizing in the design space. The model updating software ZDXZ-V 1.0 of structural dynamics, is developed based on the MSC Patran/Nastran software platform. Finally, the effectiveness of the model updating method is also examined by applying it to a liquid rocket nozzle. The results indicate that the relative errors of the first three-order modal frequencies are less than 2% compared to the experimental data. The minimal MAC value of the shape correlation is greater than 0.9 while the dynamic conformance of the nozzle model is improved remarkably. The model precision can meet the requirements of engineering applications. Consequently, the model updating strategy has been proven to be efficient and robust. It is suitable for updating the dynamics FE models of the large complex engineering structures.