基于卡箍位置灵敏度分析的空间管路系统避振优化

Vibration avoidance optimization of spatial pipeline system based on clamp position sensitivity analysis

在航空发动机管路的设计阶段,需要尽量避开航空发动机转子的激振频率以提高管路系统的工作可靠性。以两端通过管接头固定的多卡箍支撑空间管路系统为对象,研究了按有限元理论对其进行动力学建模,进而实施基于卡箍位置灵敏度分析的空间管路系统避振优化的方法。首先,提出了基于“以直代曲”和“坐标转换”的面向任意形状空间管体的有限元建模方法,在此基础上用两个弹簧对模拟卡箍的支撑,以及分别采用“变截面梁”和“弹簧单元”模拟管接头的结构及弹性约束,通过对整体坐标系下各单元进行组集创建了管路系统的有限元模型。然后,通过切比雪夫多项式进行卡箍位置全局及局部灵敏度分析,在此基础上提出了局部灵敏度-卡箍布局寻优方法。最后,以两端带有管接头的3卡箍支撑的空间管路为实例,通过试验校验了空间管路有限元建模方法的合理性。进一步通过全局灵敏度分析减小了设计变量的个数,通过局部灵敏度-卡箍布局寻优方法得到了使管路系统基频最大的卡箍布局。相较于初始状态优化后获得的基频提高了50.54%,且和遗传算法相比,所描述的方法在求解效率上提升了86.87倍。

In design stage of aircraft engine pipelines,it is necessary to avoid excitation frequencies of aircraft engine rotor as much as possible to improve the reliability of pipeline system.Here,a dynamic modeling method based on finite element theory was studied for a multi-clamp supported spatial pipeline system fixed by pipe joints at both ends,and a vibration avoidance optimization method for the spatial pipeline system based on clamp position sensitivity analysis was implemented.Firstly,a finite element modeling method for an arbitrarily shaped spatial pipe body based on“replacing curves with straight lines”and“coordinate transformation”was proposed.Then,2 spring pairs were used to simulate clamp support,and structures and elastic constraints of pipe joints were simulated using“variable cross-section beams”and“spring elements”,respectively.The finite element model of the pipeline system was created by assembling each element in the overall coordinate system.Furthermore,global and local sensitivity analyses of clamp positions were performed using Chebyshev polynomials,and then a local sensitivity-clamp layout optimization method was proposed.Finally,taking a spatial pipeline supported by 3 clamps with pipe joints at both ends as an example,the rationality of the finite element modeling method for spatial pipelines was verified through tests.Global sensitivity analysis was further used to reduce the number of design variables,and the local sensitivity-clamp layout optimization method was used to obtain the clamp layout maximizing the fundamental frequency of the pipeline system.It was shown that compared to the fundamental frequency obtained after initial state optimization,it increases by 50.54%;compared with genetic algorithm,the described method improves the solving efficiency by 86.87 times.