Research On Aerodynamic Performance Of Typical Airfoil And Aviation Material Safety Analysis

With the continuous improvement of the comprehensive performance of aerospace products,the technical requirements on the geometry of the aircraft components are increasing in its complexity in terms of better cruise performance and aerodynamic stability.To obtain greater economic benefits on modern large-scale civil aircraft,the aerodynamic performance of wings has increasing comprehensiveness on its specifications.Under the prerequisite of increasing performance without compromising its safety,the angle of attack can be increased as much as possible to increase the lift.However,when the angle of attack is too large,a separation vortex will be formed on the upper surface of the wing to induce turbulence,resulting in a significant drop in the lift coefficient and occurrence of unpredictable accident attributed to the aircraft stall.At the same time,due to the complex loading of various parts of the aircraft,aviation materials have higher performance requirements,and the performance of the materials,especially the low-cycle fatigue performance,is more stringent.General light aircraft often use NACA four-digit airfoil.This article takes NACA2412 airfoil which is commonly used in general light aircraft as an example,explores the turbulence model suitable for aviation,and analyzes the aerodynamic performance of the airfoil.Using the STAR-CCM + software,the aerodynamic performance parameters of the NACA2412 airfoil were obtained through simulation experiments and combined with the wind tunnel test results,the pressure distribution at various points of the airfoil at different angles of attack was analyzed to determine the trend of lift against the angle of attack as well as the critical angle of attack in stall.To ensure flight safety,the angle of attack needs to be stabilized within a range that provides stable lift,which requires higher longitudinal stability of the aircraft.Therefore,this paper discusses and analyzes the static and dynamic longitudinal stability of the aircraft from two perspectives of short-term oscillation and long-term oscillation and establishes a dynamic stability transfer equation to judge the safety of the angle of attack correction model.This article also focuses on the typical passenger cabin as the research object,analyzes the stress and fatigue of the fuselage cabin under different load types during cruising,and uses CES Edu Pack software for material selection analysis and safety performance evaluation.Under the condition of confirming the cabin working conditions,the ABAQUS simulation was performed on the 2024 aluminum alloy and the TB17 titanium alloy under static and dynamic stress crack growth simulation experiments to analyze the fatigue properties of the material.The simulation of stress fields of 2024 aluminum alloy and TB17 titanium alloy sample plates with three different initial crack lengths under static and dynamic loads and solving the stress intensity factor by hand calculation and simulation will be conducted.To ensure that the materials will not fail under normal working conditions,simulation and analysis of the hysteresis loops of different materials with different cycles and different hardening modes under low cycle fatigue have been done.