基于部件级模型修正的某发动机整机动态特性计算

Calculation of Engine Dynamic Characteristics Based on Component-level Model Correction

针对型号研制初期产品缺乏试验、动力学识别误差较大的问题,采用一种经修正的简化模型计算发动机动特性。首先,使用多类型有限元单元进行整机刚度等效简化建模及单元耦合,计算得到喷管延伸段的结构模态特性;然后,对比喷管延伸段简化模型、全三维模型与振动台模态试验结果,以100 Hz内主要模态频率为优化目标,使用多目标遗传优化算法对简化模型进行修正重构;最后,计算重建后整机模型动态特性,得到发动机模态特性与各部件位置谐响应分布规律。该模型修正方法在型号研制初期不具备试验条件情况下,能通过多轮模型修正得到较为准确的整机动特性。

Aiming at the problem of lack of test and the large dynamic test error in the initial stage of model development,a modified simplified model was adopted to calculate the engine maneuvering characteristics.First,according to the principle of stiffness equivalence,the simplified modeling and element coupling were carried out by using multi type finite element,and the structural modal characteristics of the nozzle were calculated.Then,the results of the simplified model,the full three-dimensional model and the shaking table modal test of the nozzle section were compared.Taking the modal frequencies within 100 Hz as the optimization objective,the multi-objective genetic optimization algorithm was used to modify and reconstruct the simplified model.In the end,the dynamic characteristics of the whole engine model were calculated and reconstructed,and the modal characteristics of the engine and the distribution law of the harmonic response of each component were obtained.The model correction method could obtain more accurate characteristics of the engine through multi wheel model correction under lacking of the experiment equipment.