Multi-pipe Bundle Layout Optimization For Aero-engine Based On Double-clamp Constraints

To improve the stability and reliability of aero-engine,a perfect pipeline system should consider not only the pipe layout optimization,but also the clamp layout optimization.At the same time,to improve the aesthetics of the overall design of the pipe system and facilitate the installation and maintenance of subsequent equipment,it is necessary to optimize the bundle layout of the pipe system.As one of the clamp types,double-clamp has unique mechanical characteristics.In the optimal design of bundle layout of pipe system,it not only makes the pipe system more regular,but also is very important to improve the vibration performance of the system.At present,in the research of multi-pipe layout,either the pipe system is laid in bundles or the pipe system is laid in bundles without considering the constraints of double-clamp.In this paper,according to the corresponding engineering rules and layout optimization objectives,based on the establishment of a simplified aero-engine layout space simulation model,the establishment of a parametric geometric wireframe model according to the structural characteristics of the double-clamp,and the improvement of the traditional multi-objective optimization algorithm,the bundle layout optimization problem of aero-engine pipe system is studied.Without considering the constraints of double-clamp,according to the rules and objectives of three-dimensional multi-pipe bundle layout,the optimization method of multi-pipe bundle layout is established.At the same time,considering the structural characteristics of the double-clamp and the assembly coupling relationship between the double-clamp and the pipe,an optimization method of multi-pipe bundle layout based on the double-clamp constraints is proposed.For the shortcomings of the traditional NSGA-Ⅱ（Non-dominated Sorting Genetic Algorithm）,an improved NSGA-Ⅱ algorithm based on COL（Chaos Operation-Based Learning and Normal Crossover and Levy Variation）is constructed by improving its population initialization,crossover and mutation operators.For the optimization problem of multi-pipe bundle layout,based on the analysis of the three-dimensional multi-pipe bundle layout path mode,a polar coordinate coding method is designed with the pipe path node as the decision variable.The total length of pipe path and the distance between pipe and gearbox surface are taken as the optimization objectives,and the bundle layout rules are integrated into consideration to complete the establishment of the model,the improved NSGA-Ⅱ is used to solve the bundle layout model.For the problem of multi-pipe bundle layout based on double-clamp constraints,according to the assembly coupling relationship between pipe and double-clamp,the pipe path mode based on double-clamp constraints is established,and the corresponding pipe path control nodes are generated.Considering the pipe layout and double-clamp layout rules,the pipe double-clamp layout algorithm based on improved NSGA-Ⅱ is constructed.The optimal solution of pipe layout and double-clamp arrangement is realized at the same time;At the same time,according to the relative position of the starting point port of the pipe,the pipe grouping and layout sequence planning method based on cluster analysis is proposed,and the pipeline double-clamp layout algorithm is called to complete the multi-pipe bundle layout planning;In the pipe design stage,the double-clamp layout is considered in the proposed layout method,which realizes the automatic planning of double-clamp layout and multi-pipe bundle layout at the same time.Siemens NX software is used to complete the simplified CAD model of aero-engine,and MATLAB software is used to realize the above optimization design programming operation.Based on the secondary development language of Grip,the spatial information extraction of layout,the layout of pipe system and the visualization of geometric parametric wireframe model of double-clamp are realized.