A Study Of Shape Optimization Of Critical Components In Aero-enignes

As the heart of an aircraft,aeroengine has a direct impact on the performance of the aircraft, and plays an important role in the field of national security and national economy. One of the most important performance indexes in aeroengine is thrust-weight ratio. Lightweight design of typical components not only can improve the thrust-weight ratio, but also bring direct economic benefits, so more and more scholars put emphasis on weight reduction of the engine.With the development of computer technology, the CAD/CAE technique is combined with optimization technology for an structural optimization design, which has become an essential part of the design phase for aeroengine. This thesis conducted the optimization with the integration of modeling software UG and finite element analysis software ANSYS, and has realized the automatic optimization process in Matlab environment. Meanwhile, this thesis introduced a global optimization method based on response surface approximation, and conducted weight optimization on a multistage disk and hollow fan blade using CORS-RBF optimization method. The thesis mainly includes three parts:The first research is conducted on the accuracy of two-dimensional simplified models of bolt holes. The computing cost of three-dimensional finite element analysis of multistage disk is expensive, and thus is commonly replaced by a two-dimensional axisymmetric model. The bolt hole models aren’t axisymmetric structures, so before a two-dimensional axisymmetric analysis, we need to assess the simulation accuracy of two-dimensional models. In addition, this paper presents a 2D and 3D mixed model analysis method to obtain high precision calculation of stress and displacement on the holesides of turbine disk, and demonstrates that the method has a high accuracy and efficiency for the calculation of stress and displacement of bolt holes, which provides a feasible and effective approach for the precise calculation of holeside.Based on the high accuracy of two-dimensional simplified models, this thesis has modeled the multistage disk with the studied two-dimensional axisymmetric model and then conducted coupling physical field simulation. On the basis of the original design of the multistage disk, the thesis carried out optimizations under two different objectives and the constraints of stress levels. Both weight reduction solutions are obtained with all constraints satisfied.In addition, this thesis studies the design method reinforcing ribs of hollow fan blade, and puts forward a parameterization modelling method based on relative curve location method to avoid geometric interference problem. The thesis focuses on the weight optimization of a hollow fan blade through changing the thickness and distribution of the inner triangular reinforcing ribs under the constraints of equivalent stress, displacement, bending and torsional frequencies. We use CORS-RBF optimization method to obtain an optimal solution with all constraints satisfied. The optimized hollow fan blade has achieved nearly 20% weight loss, which proved to be a well-performed optimization.