多工况载荷下航空发动机支架拓扑优化设计

Topological optimization design of aero-engine support structure under multiple loading conditions

将基于变密度法的拓扑优化技术引入到航空发动机外部支撑结构(例如附件支架)设计中,以多工况下的总柔度为目标函数,以体积为约束函数对某发动机支架进行基于拓扑优化的结构设计。根据发动机机匣与附件的相对位置关系建立支架初始模型,开展发动机外部支架结构受力分析研究,建立了基于多工况载荷下拓扑优化和考虑强度影响的尺寸优化相结合的发动机外部支撑结构设计方法,并对最终支架结构进行强度、振动、外廓性校核评估。结果表明:最终模型最大应力出现在工况3情况下,最大主应力为345 MPa低于材料疲劳极限;支架的第1阶固有频率在发动机最高转速频率的1.25倍以上。采用该方法对某发动机外部支撑结构进行拓扑优化设计,在满足强度、振动和外廓要求的前提下,最终模型质量仅为初始模型的7.3%。基于多工况的优化结果更符合发动机实际工作需求,该方法研究具有工程应用前景。

The topological optimization technology based on the variable density method was introduced into the design of aero-engine external support structure(such as accessory support). Taking the total flexibility under multiple working conditions as the objective function and the volume as the constraint function, the structural design of an engine support based on the topological optimization was carried out. The initial model of the bracket was established according to the relative position relationship between the engine casing and the accessories, and the stress analysis of the external support structure of the engine was carried out. The design method of the external support structure of the engine was established based on the topology optimization under multi load conditions and the size optimization considering the influence of strength. The strength, vibration and profile of the final support structure were checked and evaluated. The results showed that the maximum stress of the final model appeared in condition 3, and the maximum principal stress was 345 MPa, which was lower than the fatigue limit of the material;the first natural frequency of the bracket was more than 1.25 times of the maximum speed frequency of the engine. This method was used to optimize the topology of the external support structure of an engine. On the premise of meeting the requirements of strength, vibration and contour, the final model weight was only 7.3% of the original model. The optimization results based on multi operating conditions are more in line with the actual working requirements of the engine, and the research of this method has a bright future in engineering application.