Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber Travel

Due to the complexity of the landing gear’s (LG) structural integrity and its loads under various static or dynamic working conditions, the fatigue life assessment for LG is a highly challenging task. On the basis of the whole geometric model of a large passenger aircraft’s main landing gear (MLG),...

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Main Authors: Haihong Tang, Panglun Liu, Jianbin Ding, Jinsong Cheng, Yiyao Jiang, Bingyan Jiang
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Aerospace
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Online Access:https://www.mdpi.com/2226-4310/12/1/42
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author Haihong Tang
Panglun Liu
Jianbin Ding
Jinsong Cheng
Yiyao Jiang
Bingyan Jiang
author_facet Haihong Tang
Panglun Liu
Jianbin Ding
Jinsong Cheng
Yiyao Jiang
Bingyan Jiang
author_sort Haihong Tang
collection DOAJ
description Due to the complexity of the landing gear’s (LG) structural integrity and its loads under various static or dynamic working conditions, the fatigue life assessment for LG is a highly challenging task. On the basis of the whole geometric model of a large passenger aircraft’s main landing gear (MLG), the quasi-static finite element model (FEM) of the whole MLG is established, and the high-cycle fatigue issue of the Main Fitting (MF) is studied by considering the variation in shock absorber travel (SAT). Firstly, the ground loads under actual fatigue conditions are equivalently converted into the forces acting on the center of the left and right axles of the MLG, and based on these spatial force decompositions, the magnitude and direction of the load for 12 different basic unit load cases (ULC) are obtained. That is, the stress of the MLG under actual fatigue conditions can be obtained by superimposing these ULCs. Then, considering that the SAT of the MLG varies under different fatigue conditions, and to reduce the number of finite element (FE) simulations, this article simplifies all the SAT experienced by the MLG into seven specific values, so as to establish seven quasi-static FEMs of the MLG with the specified stroke of the shock absorber. In this way, the fatigue stress of the MLG with any actual SAT can be obtained by interpolating the stress components of the seven FEMs. Only 84 FE simulations are needed to efficiently obtain the fatigue stress spectra from the ground load spectra. Finally, according to the material S-N curve and Miner’s damage accumulation criterion, evaluate the fatigue life of the Main Fitting. The results of the stress component interpolation and superposition method show that at least five different SATs of the whole MLG’s FEM are needed to effectively convert the fatigue loads into a stress spectrum. The fatigue life prediction results indicate that the minimum lifespan of the MF is 53164 landings, which means that the fatigue life meets the requirement design.
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spelling doaj-art-6cb49279743c48f88074ec97e97f7e592025-01-24T13:15:35ZengMDPI AGAerospace2226-43102025-01-011214210.3390/aerospace12010042Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber TravelHaihong Tang0Panglun Liu1Jianbin Ding2Jinsong Cheng3Yiyao Jiang4Bingyan Jiang5State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, ChinaState Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, ChinaState Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, ChinaState Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, ChinaState Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, ChinaState Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, ChinaDue to the complexity of the landing gear’s (LG) structural integrity and its loads under various static or dynamic working conditions, the fatigue life assessment for LG is a highly challenging task. On the basis of the whole geometric model of a large passenger aircraft’s main landing gear (MLG), the quasi-static finite element model (FEM) of the whole MLG is established, and the high-cycle fatigue issue of the Main Fitting (MF) is studied by considering the variation in shock absorber travel (SAT). Firstly, the ground loads under actual fatigue conditions are equivalently converted into the forces acting on the center of the left and right axles of the MLG, and based on these spatial force decompositions, the magnitude and direction of the load for 12 different basic unit load cases (ULC) are obtained. That is, the stress of the MLG under actual fatigue conditions can be obtained by superimposing these ULCs. Then, considering that the SAT of the MLG varies under different fatigue conditions, and to reduce the number of finite element (FE) simulations, this article simplifies all the SAT experienced by the MLG into seven specific values, so as to establish seven quasi-static FEMs of the MLG with the specified stroke of the shock absorber. In this way, the fatigue stress of the MLG with any actual SAT can be obtained by interpolating the stress components of the seven FEMs. Only 84 FE simulations are needed to efficiently obtain the fatigue stress spectra from the ground load spectra. Finally, according to the material S-N curve and Miner’s damage accumulation criterion, evaluate the fatigue life of the Main Fitting. The results of the stress component interpolation and superposition method show that at least five different SATs of the whole MLG’s FEM are needed to effectively convert the fatigue loads into a stress spectrum. The fatigue life prediction results indicate that the minimum lifespan of the MF is 53164 landings, which means that the fatigue life meets the requirement design.https://www.mdpi.com/2226-4310/12/1/42fatigue lifeshock absorber travelunit load splitstress component superpositionmain landing gear
spellingShingle Haihong Tang
Panglun Liu
Jianbin Ding
Jinsong Cheng
Yiyao Jiang
Bingyan Jiang
Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber Travel
Aerospace
fatigue life
shock absorber travel
unit load split
stress component superposition
main landing gear
title Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber Travel
title_full Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber Travel
title_fullStr Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber Travel
title_full_unstemmed Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber Travel
title_short Numerical Prediction of Fatigue Life for Landing Gear Considering the Shock Absorber Travel
title_sort numerical prediction of fatigue life for landing gear considering the shock absorber travel
topic fatigue life
shock absorber travel
unit load split
stress component superposition
main landing gear
url https://www.mdpi.com/2226-4310/12/1/42
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