Degenerated Four Nodes Shell Element with Drilling Degree of Freedom

Adam, Fathelrahman M.; Mohamed, Eid S.; Hassaballa, A. E.

doi:10.9790/3021-03831020

Cited by 4 publications

(2 citation statements)

References 15 publications

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“…which is then added to the strain energy ultimately contributing to the constitutive stiffness matrix of the system. The drilling degree-of-freedom is calculated simply by penalizing the in-plane rotational shear, as for instance discussed in Adam et al [36]. Here, the drilling stiffness 𝐸 𝑑𝑟𝑖𝑙𝑙𝑖𝑛𝑔 is calculated based on the laminated composite plate stiffness component 𝐴 66 , such that:…”

Section: A Structural Modelmentioning

confidence: 99%

Design and aeroelastic analysis of truss-based modular wing structures

Silva

Guimarães

Castro

2023

AIAA SCITECH 2023 Forum

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Modular structures come with the promise of efficient manufacturing and reduced maintenance costs. The amount of modularization is usually limited by weight efficiency, meaning that the minimum weight always lies on the most customized design, where all the structural elements are allowed to be different across the structural domain. This work studies a new design approach and structural and aeroelastic optimization of wings using truss-based modular structures. Furthermore, the work proposes a new approach to structural topology, eliminating traditional elements, such as spars and ribs, and replacing them with modular truss-based structures, which are connected by spherical joints at their ends. The topological mesh of the structures are created from the Delaunay triangulation and tessellation. The structural model is based on two types of finite elements: beam and quadrilateral elements. The beam elements are defined from consistent Timoshenko elements and the quadrilaterals are based on Mindlin-Reissner kinematics using bi-linear interpolation and reduced integration to prevent shear locking. The Doublet-Lattice Method is used to predict the unsteady subsonic aerodynamics, and the P-K method is used to compute the aeroelastic system solution. For the examples and case studies, a reference wing geometry from the FLEXOP project is used as a baseline. Two optimizations are proposed, where in all the objective functions are to minimize the structural weight of the wing and to maximize the flutter speed. The first optimization has as design variables the number of control points, or nodes, in each airfoil and the number of sections along the span. In the second optimization, the external diameters and thicknesses of each of the modular structures are individually optimized, even eliminating unnecessary ones. The results show that it is possible to obtain relatively light wings that meet the structural and aeroelastic requirements; however, the definition of the optimization parameters directly influence the mesh generation and computational cost of the optimization. Above all, modular structures have proved to be a good strategy in the design of structures for new wing concepts.

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Section: A Structural Modelmentioning

confidence: 99%

Design and aeroelastic analysis of truss-based modular wing structures

Silva

Guimarães

Castro

2023

AIAA SCITECH 2023 Forum

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“…The generalized formulation of selective reduced integration proposed by Hughes [ 22 ] has been employed in this work. In addition, the four-node quadrilateral degenerated shell element [ 23 ] is utilized in the intensive analysis.…”

Section: Basic Theorymentioning

confidence: 99%

Analysis of Deep Drawing Process for Stainless Steel Micro-Channel Array

2017

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The stainless steel bipolar plate has received much attention due to the cost of graphite bipolar plates. Since the micro-channel of bipolar plates plays the role of fuel flow field, electric connector and fuel sealing, an investigation of the deep drawing process for stainless steel micro-channel arrays is reported in this work. The updated Lagrangian formulation, degenerated shell finite element analysis, and the r-minimum rule have been employed to study the relationship between punch load and stroke, distributions of stress and strain, thickness variations and depth variations of individual micro-channel sections. A micro-channel array is practically formed, with a width and depth of a single micro-channel of 0.75 mm and 0.5 mm, respectively. Fractures were usually observed in the fillet corner of the micro-channel bottom. According to the experimental results, more attention should be devoted to the fillet dimension design of punch and die. A larger die fillet can lead to better formability and a reduction of the punch load. In addition, the micro-channel thickness and the fillet radius have to be taken into consideration at the same time. Finally, the punch load estimated by the unmodified metal forming equation is higher than that of experiments.

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Koiter–Newton analysis of thick and thin laminated composite plates using a robust shell element

Liang

2017

Composite Structures

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Degenerated Four Nodes Shell Element with Drilling Degree of Freedom

Cited by 4 publications

References 15 publications

Design and aeroelastic analysis of truss-based modular wing structures

Design and aeroelastic analysis of truss-based modular wing structures

Analysis of Deep Drawing Process for Stainless Steel Micro-Channel Array

Koiter–Newton analysis of thick and thin laminated composite plates using a robust shell element

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