Review: Computational methods for bird strike simulations: A review

FE analysis of geometry effects of an artificial bird striking an aeroengine fan blade

https://isiarticles.com/bundles/Article/pre/pdf/26739.pdf

Turbine blade temperature calculation and life estimation - a sensitivity analysis

A comprehensive three-dimensional nonlinear finite element analyses were carried out to examine the effects of the geometry and the incidence angle of canonical 4-lb bird striking a stationary fan blade using LS-DYNA. Three aspects of the work were accordingly examined. The first was concerned with the modeling framework used. The second with the constitutive law that governs the behaviour of the bird. The third was concerned with the influence of the geometry and the angle of incidence of the bird on the integrity of the blade. This article combines and extends the earlier works on both the Lagrangian modeling methodology (Mao et al. AIAA J. Aircr. 44(2), 583–596, 2007) and the bird geometry studies (Meguid et al. 2008) in systematic and integrated manner. Both the bird and the blade were simulated in a Lagrangian framework. Furthermore, the homogenized fluidic constitutive equation of the bird follows the Brockman hydrodynamic model, while the blade is modeled as a viscoplastic material of the Perzyna type. The study focused on the three most-frequently used configurations in the literature; namely, hemispherical-ended cylinder, straight-ended cylinder, and ellipsoid, at various length-to-diameter aspect ratios. The results show that the initial contact area between the bird and target in the early phase of the impact event would have a significant effect on the peak impact force. Normal incidence results in maximum impact forces and plastic strains leading to severe deformation. For the case where the incidence angle is equal to or larger than 60°, the impact forces are significantly reduced and the blade deformation remains within the elastic range. The maximum impact force and the resulting plastic strain are not merely governed by the size of the bird but also its density.

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Transient three dimensional finite element analysis of a bird striking a fan blade

Bird strike is a serious problem that affects both commercial and military aircrafts. Systematic modeling and simulation of bird strikes are severely lacking, especially for cases involving engine, fan blades, and casings. In the present investigation, explicit 3-D finite element analysis using LS-DYNA is carried out to study the nonlinear transient response of a bird striking a fan system. The bird strike is simulated using Lagrangian blade-bird formulations. The bird is modeled as a fluid jet with a homogenized fluidic constitutive relation, using the Brockman hydrodynamic model, which was found to be the most appropriate. The present simulations are validated using a benchmark test of a bird striking a rigid target that is reported in the literature. Following this validation, a reference case of a bird striking a flexible fan blade was set up and used as the reference case in a series of parametric studies. The effect of bird velocity and its size are examined and attention is given to strikes involving larger birds so as to address the lack of data in this area.

Finite Element Modeling of a Bird Striking an Engine Fan Blade

An extensive analytical and experimental program has been undertaken to investigate the Foreign Object Damage resistance capabilities of external components for small gas turbofan engines. A transient nonlinear impact analysis has been used to predict the structural response of fan blades under bird ingestion conditions. This analysis is based on finite elements, a three-dimensional bird load model, and an interactive structure-to-bird contact algorithm. Experiments were designed and carried out to record large blade deformations during bird impact, and were used to validate and calibrate the analytical models. The analytical models and testing program are described, and dominant fan blade response and failure modes are presented. Predicted results demonstrate good correlation with tests. Analysis application to fan blade design and other engine components is recommended.

Analytical and Experimental Simulation of Fan Blade Behavior and Damage Under Bird Impact

The objective of this paper is to present a complete three-dimensional life prediction system which was developed for turbine engine components. It will deal primarily with turbine blades and vanes which are subjected to hostile thermal and combustion environments under load which creates cyclic and/or steady multiaxial stress and strain fields. All of the above factors combined are detrimental to the service life of these components and need very careful consideration at the design stage. The developed multiaxial system for a mission includes evaluation of transient metal temperatures, corresponding elastic and inelastic strains, creep strains, and subsequently creep/fatigue lives. The calculations are performed using the ductility exhaustion method. The maximum principal normal strain ranges used in the life analysis are found by a developed procedure for a multiaxial system. The concept is based on analyzing all of the time steps computed in the mission, in order to develop the maximum principal normal strain range whose direction and magnitude is strictly a function of the component geometry and mission loading. The mission creep is then developed by maximizing a cumulative creep function. Directional consistency is maintained in accumulating creep/fatigue damage with respect to the incurred multiaxial stress and strain fields. Also the most damaging mission modes (creep or fatigue) will be separated. Further development in the model includes the capability of analytically obtaining the fatigue curve for any ratio R of minimum to maximum strain using baseline fatigue material properties (R = −1.0). Application of the model to an actual uncooled vane correlates well with test rig development experience.

Multiaxial Life Prediction System for Turbine Components

The objective of this paper is to present a complete 3–D life prediction system which was developed for turbine engine components. It will primarily deal with turbine blades and vanes which are subjected to hostile thermal and combustion environments under load which creates cyclic and/or steady multiaxial stress and strain fields. All of the above factors combined are detrimental to the service life of these components and need very careful consideration at the design stage. The developed multiaxial system for a mission includes evaluation of transient metal temperatures, corresponding elastic and inelastic strains, creep strains and subsequently creep/fatigue lives. The calculations are performed using the ductility exhaustion method. The maximum principal normal strain ranges used in the life analysis are found by a developed procedure for a multi-axial system. The concept is based on analyzing all of the time steps computed in the mission, in order to develop the maximum principal normal strain range whose direction and magnitude is strictly a function of the component geometry and mission loading. The mission creep is then developed by maximizing a cumulative creep function. Directional consistency is maintained in accumulating creep/fatigue damage with respect to the incurred multiaxial stress and strain fields. Also the most damaging mission modes (creep or fatigue) will be separated. Further development in the model includes the capability of analytically obtaining the fatigue curve for any ratio (R) of minimum to maximum strain using baseline fatigue material properties (R=−1.0). Application of the model to an actual uncooled vane correlates well with test rig development experience.

The objective of this paper is to present a complete 3–D life prediction system which was developed for turbine engine components. It will primarily deal with turbine blades and vanes which are subjected to hostile thermal and combustion environments under load which creates cyclic and/or steady multiaxial stress and strain fields. All of the above factors combined are detrimental to the service life of these components and need very careful consideration at the design stage.The developed multiaxial system for a mission includes evaluation of transient metal temperatures, corresponding elastic and inelastic strains, creep strains and subsequently creep/fatigue lives. The calculations are performed using the ductility exhaustion method. The maximum principal normal strain ranges used in the life analysis are found by a developed procedure for a multi-axial system. The concept is based on analyzing all of the time steps computed in the mission, in order to develop the maximum principal normal strain range whose direction and magnitude is strictly a function of the component geometry and mission loading. The mission creep is then developed by maximizing a cumulative creep function. Directional consistency is maintained in accumulating creep/fatigue damage with respect to the incurred multiaxial stress and strain fields. Also the most damaging mission modes (creep or fatigue) will be separated. Further development in the model includes the capability of analytically obtaining the fatigue curve for any ratio (R) of minimum to maximum strain using baseline fatigue material properties (R=−1.0). Application of the model to an actual uncooled vane correlates well with test rig development experience.Copyright © 1986 by ASME

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R. N. Tadros

Papers

Analytical and Experimental Simulation of Fan Blade Behavior and Damage Under Bird Impact

Multiaxial Life Prediction System for Turbine Components

Multiaxial Life Prediction System for Turbine Components

Multiaxial Life Prediction System for Turbine Components