Response Analysis Of Bird Impact Engine Blade Based On Smoothed Particle Hydrodynamics Method And Finite Element Method Coupling

Aero engine is an important part of the aircraft,and related to the safety of the flight and the performance of the aircraft.In order to reduce economic losses caused by bird strikes,it is necessary to study the damage mechanism of the structure,and use the numerical simulation method to conduct researches,which is of great significance to improve the crashworthiness of the structure and ensure the safety of people’s lives and properties.This thesis introduces the basic theory of SPH(Smoothed Particle Hydrodynamics method),including integral interpolation theory,basic equations of fluid dynamics in SPH form,smooth kernel function,neighborhood search method and solution of explicit time integral.The procedure of SPH-FEM coupling calculation solution includes: conversion of FEM units to SPH particles,calculation of contact force between units and particles,and so on.A kinematic model of the blade being impacted by a cylindrical object is established.From the energy point of view,the damage analysis of the different forms of the model is carried out,and the energy consumptions of the blades caused by the local depression,partial material loss,crack generation and expansion,and edge curling are discussed.The target model which partial position rigidity of cylindrical soft body oblique impact is studied and the load characteristic is analyzed.The SPH and finite element coupling method is used to simulate the process of bird striking on a rigid target and high-speed rotating engine blades.Considering the influence of impact environment factors such as bird attitude angle and bird shape,the damage of highspeed rotating blades to bird collision is considered.The change rule of bird-strike response is obtained when a set of the bird’s attitude angles are chosen as 0。,22.5。,45。,67.5。and 90。,respectively.The generated impact force,the energy released from the bird body,the von mises stress of the blade root units as well as the displacement of the tip nodes all become larger as the attitude angle increases.It means that the damage to the structure is more serious by the collision in this configuration.This is because the impact force is affected by the cross-sectional area of the bird body,which provides a reference for the design and optimization of the aircraft structure.