scholarly journals A new fluid structure coupling

2007 ◽  
pp. 521-536
Author(s):  
Nicolas Aquelet ◽  
Benjamin Tutt
Keyword(s):  
Finite Element ◽  
Flow Model ◽  
Air Flow ◽  
Coupling Method ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Interaction Forces ◽  
Porous Flow ◽  
Lagrangian Finite Element ◽  
Updated Lagrangian

The modelling of parachutes at Irvin Aerospace Inc. was based on the penalty Euler-Lagrange coupling method to compute the interaction between an Arbitrary Lagrange Euler formulation for the air flow and an updated Lagrangian finite element formulation for the canopy dynamics. This approach did not permit the effect of fabric porosity to be accounted for. In this paper, a new porosity Euler-Lagrange coupling models the fabric permeability by assessing the interaction forces based on the Ergun porous flow model. This paper provides validations for the technique when considering parachute applications and discusses the interest of this development to the parachute designer.

scholarly journals Porous parachute modelling with an Euler-Lagrange coupling

2007 ◽  
pp. 385-399
Author(s):  
Nicolas Aquelet ◽  
Jason Wang
Keyword(s):  
Porous Medium ◽  
Flow Model ◽  
Test Case ◽  
Element Formulation ◽  
Porous Flow ◽  
Air Stream ◽  
Thin Porous Media ◽  
Coupling Force ◽  
Lagrangian Finite Element ◽  
Updated Lagrangian

A newly developed approach for tridimensional fluid-structure interaction with a deformable thin porous media is presented. The method presented couples a Arbitrary Lagrange Euler formulation for the fluid dynamics and a updated Lagrangian finite element formulation for the thin porous medium dynamics. The interaction between the fluid and porous medium are handled by a Euler-Lagrange coupling, for which the fluid and structure meshes are superimposed without matching. The coupling force is computed with an Ergun porous flow model. As test case, the method is applied to an anchored air parachute placed in an air stream.

Euler-Lagrange Coupling With Deformable Porous Shells

2006 ◽  
Author(s):  
N. Aquelet ◽  
J. Wang ◽  
B. A. Tutt ◽  
I. Do ◽  
H. Chen
Keyword(s):  
Porous Medium ◽  
Flow Model ◽  
Test Case ◽  
Element Formulation ◽  
Porous Flow ◽  
Air Stream ◽  
Thin Porous Media ◽  
Coupling Force ◽  
Lagrangian Finite Element ◽  
Updated Lagrangian

A newly developed approach for tridimensional fluid-structure interaction with a deformable thin porous media is presented under the framework of the LS-DYNA software. The method presented couples a Arbitrary Lagrange Euler formulation for the fluid dynamics and a updated Lagrangian finite element formulation for the thin porous medium dynamics. The interaction between the fluid and porous medium are handled by a Euler-Lagrange coupling, for which the fluid and structure meshes are superimposed without matching. The coupling force is computed with an anisotropic Ergun porous flow model. As test case, the method is applied to an anchored porous MIL-c-7020 type III fabric placed in an air stream.

A Simple Total-Lagrangian Finite-Element Formulation for Nonlinear Behavior of Planar Beams

2018 ◽  
Author(s):  
Enrico Babilio ◽  
Stefano Lenci
Keyword(s):  
Finite Element ◽  
Theoretical Model ◽  
Finite Difference ◽  
Shear Angle ◽  
Difference Schemes ◽  
Finite Element Formulation ◽  
Finite Difference Schemes ◽  
Element Formulation ◽  
Beam Model ◽  
Lagrangian Finite Element

The present contribution reports some preliminary results obtained applying a simple finite element formulation, developed for discretizing the partial differential equations of motion of a novel beam model. The theoretical model we are dealing with is geometrically exact, with some peculiarities in comparison with other existing models. In order to study its behavior, some numerical investigations have already been performed through finite difference schemes and other methods and are reported in previous contributions. Those computations have enlightened that the model under analysis turns out to be quite hard to handle numerically, especially in dynamics. Hence, we developed ad hoc the total-lagrangian finite-element formulation we report here. The main differences between the theoretical model and its numerical formulation rely on the fact that in the latter the absolute value of the shear angle is assumed to remain much smaller than unity, and strains are piecewise constant along the beam. The first assumption, which actually simplifies equations, has been taken on the basis of results from previous integrations, mainly through finite difference schemes, which clearly showed that, while other strains can achieve large values in their range of admissibility, shear angle actually remains small. The second assumption led us to define a two-nodes constant-strain finite element, with a fast convergence, in terms of number of elements versus solution accuracy. Although, at the present stage of this ongoing research, we have only early results from finite elements, they appear encouraging and start to shed new light on the behavior of the beam model under analysis.

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