Finite element simulation of high-speed soft-body impacts

Stoll, Frederick; Brockman, R. A.

doi:10.2514/6.1997-1093

Cited by 31 publications

(21 citation statements)

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“…However, only 24.4%, 37.5%, and 40.2% of the initial momentum of the bird are finally transmitted to the blade in the Z-direction, for the straight-ended cylinder, hemispherical-ended cylinder, and ellipsoidal bird, respectively. The present simulation has been successful in suppressing the stairway profiles of the impulse accumulation, which was frequently observed in earlier results, such as Stoll and Brockman [25], and Langrand et al [12]. Fig.…”

Section: Article In Presssupporting

confidence: 85%

“…This can be attributed to the fine mesh density used in discretizing the bird geometry. Specifically, we used a bird-to-element length ratio of about 32, compared with 8 used by Stoll and Brockman [25], and Airoldi and Cacchione [14]. The peak value of the pressure from the present simulation is about 20% lower than that of the experimental data, and this difference is probably due to the use of water-compressible modules for the bird's material model, which underestimates the behavior of a real bird.…”

Section: Resultsmentioning

confidence: 95%

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

Meguid

Mao

2008

International Journal of Impact Engineering

111

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Section: Article In Presssupporting

confidence: 85%

Section: Resultsmentioning

confidence: 95%

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

Meguid

Mao

2008

International Journal of Impact Engineering

111

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“…The losses result in 37.5%, 8.0% and 1.7% of the initial momentum of the bird being transmitted to the blade in the z-, x-and y-direction, respectively. The present simulation does not show the stairway profiles during the process of the impulse accumulation, which was observed in the simulation of Stoll and Brockman [15] due to the presence of undesired spiky contact-force histories in their results. The final deformation of the blade will result in undesirable unbalanced centrifugal force in the fan assembly, residual aerodynamic performance and aero-elastic instability [8].…”

Section: Effects Of Incidence Anglecontrasting

confidence: 62%

“…This can be attributed to the fine mesh density used in discretising the bird geometry. Specifically, bird-toelement length ratio of 32 was used, as compared to 8 used in earlier literature [1,15].…”

Section: Validation Testmentioning

confidence: 99%

Effects of incidence angle in bird strike on integrity of aero-engine fan blade

Mao

Meguid

2009

International Journal of Crashworthiness

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The possibilities of blade deformation and even fracture, the need for subsequent containment and reduction in thrust and power supply make bird strikes to aero-engine fan blades very serious events. Due to the different bird-plane flight paths and the different types of turbofan engines, the incidence angle between the bird and the engine fan blade can vary within a wide range. The present explicit non-linear three-dimensional finite-element analyses examine in detail the effect of the incidence angle when a canonical 4-lb bird strikes a typical engine fan blade, using the commercial code LS-DYNA. Both the bird and the blade are simulated in a Lagrangian framework. The homogenised fluidic constitutive equation of the bird follows the Brockman hydrodynamic model, while the blade is modelled as a viscoplastic material of the Perzyna type. It was found that normal incidence results in maximum impact forces and plastic strains leading to severe deformation. For the case in which 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. In addition, this work also provides a theoretical calculation for the bird Hugoniot pressure by assuming it as a high-speed soft-body impactor, thus providing a means for obtaining a quick conservative upper bound solution. Nomenclature (in SI units)A cross = Cross-sectional area of the bird, A cross = π 4 D 2 (m 2 ) C i = Compressive modulus of the bird material (Pa) D = Diameter of the bird (m) E = Young's modulus of the blade material (Pa) F = Impact or contact force between the bird and the target (N) I = Impulse between the bird and the target, I = ∝ 0 F · dt (N s) I ad = Normalised Impulse, I ad = I m·ẇ 0 L = Length of the bird (m) M = Mass of the bird (kg) P = Pressure (Pa) P TH s = Theoretical stagnation pressure, P TH s = 1 2 ρ 0 ·ẇ 2 0 (Pa) P ad = Normalised impact pressure, P ad = F/A cross P TH s T = Normalised time, T = t T 0 = t L/ẇ 0 T 0 = Nominal impact duration, T 0 = L/ẇ 0 (s) c, p = Strain-rate parameters, c = 40.0 s −1 , p = 5.0 d α = Damping coefficient t = Time (s) u, v, w = Displacements in x-, y-and z-direction (m) * Corresponding author. Email: r.mao@tudelft.nlẇ 0 = Initial velocity of the bird (m/s) x, y, z = Cartesian coordinates (m) θ = Incidence angle (degree) σ ij = Stress tensor (Pa) δ ij = Kronecker delta symbol e ij = Strain rate tensor (s −1 ) ρ = Instantaneous mass density of the bird (kg/m 3 ) ρ 0 = Initial mass density of the bird (kg/m 3 ) µ = Mass density change ratio of the bird, µ = ρ ρ 0 − 1 ν = Poisson ratio of the fan blade material IntroductionOf all foreign object damage to aircraft, 90% can be attributed to bird strikes. These bird-strike events place both aircraft and passengers at risk. Bird-strike statistics indicate that over 400 people have been killed worldwide as a result of bird strikes [17]. In the United States, damage due to bird strike costs the aviation industry over US$600 million annually [21]. The alarming frequency of bir...

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“…Moreover, in an explicit FE analysis, the time step is determined by the dimension of the smallest element; severe mesh distortion causes the time step to decrease to an unacceptably low value for calculations to continue. 2,5 Another approach is the Euler approach, in which the meshing grids and the material are independent. The size and location of the meshing grids remains unchanged during an analysis, and material flows between the grids.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of a bird impact on a composite aerodynamic brake wing of a high-speed train

Zuo

Zhu

2013

Proceedings of the Institution of Mechanical Engineers, Part F:

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Experimental bird strike tests were conducted in which a 2.6-kg dead chicken was projected at a speed of 500 km/h to hit a raised aerodynamic brake wing. The brake wing was fabricated with a sandwich of composite material as its skin and polymethacrylimide foam as its core. Pre-test numerical analyses of bird strikes were performed using the LS-Dyna solver code, an Arbitrary Lagrangian Eulerian model of the bird, and a Lagrangian model of the brake wing. The numerical and experimental results were well correlated, confirming the validity of the finite element model and calculation approach. Finally, bird strikes were conducted on a brake wing extended to 75 and 90 to determine the difference between the two conditions on the basis of effective wind-drag area. Impact, failure after impact and high strength at impact properties were investigated for a composite of carbon and glass fibre laminate.

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Finite element simulation of high-speed soft-body impacts

Cited by 31 publications

References 0 publications

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

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

Effects of incidence angle in bird strike on integrity of aero-engine fan blade

Numerical simulation of a bird impact on a composite aerodynamic brake wing of a high-speed train

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