scholarly journals Smooth Particle Hydrodynamics Birdstrike Analysis on Aircraft Wing Leading Edge

2021 ◽  
Vol 15 (3) ◽  
Keyword(s):  
Leading Edge ◽  
Smooth Particle Hydrodynamics ◽  
Aircraft Wing ◽  
Particle Hydrodynamics

scholarly journals Birdstrike Analysis on Leading Edge of an Aircraft Wing Using a Smooth Particle Hydrodynamics Bird Model

2010 ◽  
Author(s):  
Vinayak Walvekar ◽  
Chandrashekhar K. Thorbole ◽  
Prasanna Bhonge ◽  
Hamid M. Lankarani
Keyword(s):  
Finite Element ◽  
Structural Damage ◽  
Human Life ◽  
Computational Modelling ◽  
Leading Edge ◽  
Smooth Particle Hydrodynamics ◽  
Nose Radius ◽  
Certification Procedure ◽  
Physical Testing ◽  
Particle Hydrodynamics

With the increase in air travel, the recent occurrences of birdstrikes on aircraft pose a major threat to human life; hence, there is a need to develop aircraft structures with a high resistance to such occurrences. According to the Federal Aviation Regulation (FAR 25.571) on Damage-Tolerance and Fatigue Evaluation of Structure (Amdt. 25-96), an airplane must be capable of successfully completing a flight during which likely structural damage might occur as a result of impact with a four-pound (1.8 kg) bird at sea-level cruise velocity or 0.85 percent of cruise velocity at 8,000 feet (2,400 m). Since the actual physical testing of a birdstrike is expensive, time-consuming, and cumbersome, this paper presents a methodology, based on the use of analytical finite element modeling and analysis, to certify an aircraft for a birdstrike. In actual physical testing for birdstrikes the mass of the bird might not be accurate and hence for certification purpose the computational modelling technique is more accurate and standardizes the certification procedure. The modeling and simulations are carried out as follows: the bird is modeled using the smooth particle hydrodynamics (SPH) technique in the LS-Dyna nonlinear finite element code. To validate this model, birdstrikes are carried out on rigid and deformable plates. The results, including displacement, Von-Mises stresses, forces, impulse, squash time and rise time, are obtained from the simulation, and non-dimensional values are plotted and compared with results from the test data. The detailed CAD geometry of the leading edge of an aircraft is modeled in CATIA V5. Meshing, connections, and material properties are then defined in the Altair Hypermesh 9.0 program. The results obtained from the birdstrike simulations on this leading edge are compared to data from the experiments, and the process is validated. Parametric studies are carried out by designing the aircraft leading edge for different values of nose radius and by assigning appropriate thickness values for leading-edge components and impacting the SPH-modeled bird at different velocities. The methodology and results obtained from simulation can be utilized in the initial design stages as well as for “certification by analysis” of an aircraft for birdstrike requirements as per federal regulations.

Simulation Analysis and Material Optimization of an Aircraft Wing Leading Edge When Subjected to an Artificial Bird Strike

2015 ◽  
Vol 10 (5) ◽  
Author(s):  
K. Srinivasan ◽  
Channankaiah ◽  
George P. Johnson
Keyword(s):  
Simulation Analysis ◽  
Leading Edge ◽  
Primary Objective ◽  
Impact Behavior ◽  
Bird Strike ◽  
Smooth Particle Hydrodynamics ◽  
Sph Method ◽  
Material Optimization ◽  
Particle Hydrodynamics ◽  
The Impact

Bird strike resistance is a strict certification requirement in aircraft industries, and the Federal Aviation Regulations specifically gives various specifications to be followed for certification of various parts of the aircraft. The primary objective of this research is to develop a methodology, which can be utilized to certify an aircraft for bird strike using computational methods, and the impact behavior of a 4-lb artificial bird impinging on the wing leading edge is performed using smooth particle hydrodynamics (SPH) method. The study is focused on the most-frequently used bird configuration in the literatures: namely, cylinder with hemispherical ends. The skin is modeled with an aluminum 2014 alloy, which is prominently used in aircraft industries, and aluminum 8090 alloy. The effects of impact on these materials are studied.

scholarly journals Design of a Variable-Stiffness Compliant Skin for a Morphing Leading Edge

2021 ◽  
Vol 11 (7) ◽  
pp. 3165
Author(s):  
Zhigang Wang ◽  
Yu Yang
Keyword(s):  
Composite Laminate ◽  
Large Scale ◽  
Design Method ◽  
Leading Edge ◽  
Variable Stiffness ◽  
Manufacturing Constraints ◽  
Aircraft Wing ◽  
Noise Abatement ◽  
Civil Aircraft ◽  
Final Profile

A seamless and smooth morphing leading edge has remarkable potential for noise abatement and drag reduction of civil aircraft. Variable-stiffness compliant skin based on tailored composite laminate is a concept with great potential for morphing leading edge, but the currently proposed methods have difficulty in taking the manufacturing constraints or layup sequence into account during the optimization process. This paper proposes an innovative two-step design method for a variable-stiffness compliant skin of a morphing leading edge, which includes layup optimization and layup adjustment. The combination of these two steps can not only improve the deformation accuracy of the final profile of the compliant skin but also easily and effectively determine the layup sequence of the composite layup. With the design framework, an optimization model is created for a variable-stiffness compliant skin, and an adjustment method for its layups is presented. Finally, the deformed profiles between the directly optimized layups and the adjusted ones are compared to verify its morphing ability and accuracy. The final results demonstrate that the obtained deforming ability and accuracy are suitable for a large-scale aircraft wing.

scholarly journals A parameter-free total Lagrangian smooth particle hydrodynamics algorithm applied to problems with free surfaces

2021 ◽  
Author(s):  
Kenny W. Q. Low ◽  
Chun Hean Lee ◽  
Antonio J. Gil ◽  
Jibran Haider ◽  
Javier Bonet
Keyword(s):  
Ad Hoc ◽  
Wide Spectrum ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Point Of View ◽  
Numerical Dissipation ◽  
Lagrangian Description ◽  
Smooth Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Sph Algorithm

AbstractThis paper presents a new Smooth Particle Hydrodynamics computational framework for the solution of inviscid free surface flow problems. The formulation is based on the Total Lagrangian description of a system of first-order conservation laws written in terms of the linear momentum and the Jacobian of the deformation. One of the aims of this paper is to explore the use of Total Lagrangian description in the case of large deformations but without topological changes. In this case, the evaluation of spatial integrals is carried out with respect to the initial undeformed configuration, yielding an extremely efficient formulation where the need for continuous particle neighbouring search is completely circumvented. To guarantee stability from the SPH discretisation point of view, consistently derived Riemann-based numerical dissipation is suitably introduced where global numerical entropy production is demonstrated via a novel technique in terms of the time rate of the Hamiltonian of the system. Since the kernel derivatives presented in this work are fixed in the reference configuration, the non-physical clumping mechanism is completely removed. To fulfil conservation of the global angular momentum, a posteriori (least-squares) projection procedure is introduced. Finally, a wide spectrum of dedicated prototype problems is thoroughly examined. Through these tests, the SPH methodology overcomes by construction a number of persistent numerical drawbacks (e.g. hour-glassing, pressure instability, global conservation and/or completeness issues) commonly found in SPH literature, without resorting to the use of any ad-hoc user-defined artificial stabilisation parameters. Crucially, the overall SPH algorithm yields equal second order of convergence for both velocities and pressure.

scholarly journals Formation of Prestellar Cores via Non-Isothermal Gas Fragmentation

2015 ◽  
Vol 32 ◽  
Author(s):  
S. Anathpindika
Keyword(s):  
Gravitational Instability ◽  
Gas Flows ◽  
Smooth Particle Hydrodynamics ◽  
Three Phase ◽  
Prestellar Cores ◽  
Particle Hydrodynamics ◽  
Unstable Medium ◽  
Stage Process ◽  
Isothermal Gas ◽  
Gas Accretion

AbstractSheet-like clouds are common in turbulent gas and perhaps form via collisions between turbulent gas flows. Having examined the evolution of an isothermal shocked slab in an earlier contribution, in this work we follow the evolution of a sheet-like cloud confined by (thermal) pressure and gas in it is allowed to cool. The extant purpose of this endeavour is to study the early phases of core-formation. The observed evolution of this cloud supports the conjecture that molecular clouds themselves are three-phase media (comprising viz. a stable cold and warm medium, and a third thermally unstable medium), though it appears, clouds may evolve in this manner irrespective of whether they are gravitationally bound. We report, this sheet fragments initially due to the growth of the thermal instability (TI) and some fragments are elongated, filament-like. Subsequently, relatively large fragments become gravitationally unstable and sub-fragment into smaller cores. The formation of cores appears to be a three stage process: first, growth of the TI leads to rapid fragmentation of the slab; second, relatively small fragments acquire mass via gas-accretion and/or merger and third, sufficiently massive fragments become susceptible to the gravitational instability and sub-fragment to form smaller cores. We investigate typical properties of clumps (and smaller cores) resulting from this fragmentation process. Findings of this work support the suggestion that the weak velocity field usually observed in dense clumps and smaller cores is likely seeded by the growth of dynamic instabilities. Simulations were performed using the smooth particle hydrodynamics algorithm.

scholarly journals Effect of bird-strike on sandwich composite aircraft wing leading edge

2020 ◽  
Vol 148 ◽  
pp. 102839 ◽  
Author(s):  
B. Arachchige ◽  
H. Ghasemnejad ◽  
M. Yasaee
Keyword(s):  
Leading Edge ◽  
Sandwich Composite ◽  
Bird Strike ◽  
Aircraft Wing

scholarly journals Modelling Closed-Die Forging Operations Using Total Lagrangian Smooth Particle Hydrodynamics

2019 ◽  
Author(s):  
Anthony Manson
Keyword(s):  
Large Deformation ◽  
Smooth Particle Hydrodynamics ◽  
Material Flows ◽  
Forging Process ◽  
Mesh Free ◽  
Closed Die Forging ◽  
Particle Hydrodynamics ◽  
Mesh Free Method ◽  
Large Material ◽  
Simulation Parameters

Total Lagrangian Smooth Particle Hydrodynamics (TLSPH) has been applied to a set of non-trivial, commercially interesting forging examples.Being a mesh-free method, TLSPH can conveniently simulate processes having large deformation and material separation.Test cases were designed that were characterized by large material flows having large changes in grain connectivity.The implementation used, Smooth Mach Dynamics (SMD), provided tunable simulation parameters that enabled the simulation to optimally match each case.The results showed that the TLSPH/SMD has the potential to model the metal forging process efficiently without numerical instabilities.Each case studied required adaptation of the simulation parameters to optimize the results.

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