Design of Composite Structures Using Advanced Numerical Tools

Although the mechanical integrity of a member can be highly influenced by associated stresses, determining the latter can be very challenging for finite orthotropic composites containing cutouts. This is particularly so if the external loading is not well known, a common situation in practical situations. Acknowledging the above, a finite elliptically-perforated orthotropic tensile laminate is stress analyzed by combining measured displacement data with relevant analytical and numerical tools. Knowledge of the external loading is unnecessary. Results are verified independently and the concepts are applicable to other situations. The developed technology can provide important design-type information for orthotropic composites. In particular, the ability to apply analyses for perforated composite structures which assume infinite geometry to finite geometries is demonstrated.

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Smart numerical tools for the modelling of ultrasonic testing on curved composite structures

10.1063/1.5099854 ◽

2019 ◽

Cited By ~ 1

Author(s):

Alexandre Imperiale ◽

Edouard Demaldent ◽

Nicolas Leymarie ◽

Sylvain Chatillon ◽

Pierre Calmon

Keyword(s):

Ultrasonic Testing ◽

Composite Structures ◽

Numerical Tools

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A New Trefftz Based Finite Element for Static Analysis of Laminated Composite Structures

Volume 12: Advanced Materials: Design, Processing, Characterization, and Applications ◽

10.1115/imece2019-11116 ◽

2019 ◽

Author(s):

Subhasankar Dwibedi

Keyword(s):

Finite Element ◽

Composite Materials ◽

Composite Structures ◽

Laminated Composite ◽

Bench Mark ◽

Element Analysis ◽

Laminated Composite Structures ◽

Element Approach ◽

Numerical Tools ◽

Trefftz Finite Element

Abstract Composite materials have been widely used in industries for several years owing to their capability to perform better than homogeneous isotropic materials. Numerical tools like finite element method are efficiently used for analysis of structures made of composite materials. However, for complex shapes or geometries of structures, it becomes uneconomical (computational resource wise) to use Rayleigh-Ritz based finite element analysis. An unique Trefftz based finite element has been developed in this article to efficiently fill the gap in the above mentioned scenario. Hybrid-Tefftz finite element method’s flexibility to use arbitrary shaped elements comes handy in modelling complex geometries. The developed hybrid-Trefftz finite element approach has been used on symmetric angle-ply laminated composite plate and the obtained results have been compared with bench mark solutions. The present method proposes an approach for development of hybrid-Trefftz type finite elements, by which analysis of antisymmetric structures is also possible, an area of research which has been less explored by such approach as revealed from survey of available open literature.

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Solid Truss to Shell Numerical Homogenization of Prefabricated Composite Slabs

Materials ◽

10.3390/ma14154120 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4120

Author(s):

Natalia Staszak ◽

Tomasz Garbowski ◽

Anna Szymczak-Graczyk

Keyword(s):

Composite Structures ◽

Homogenization Method ◽

Fe Model ◽

Structural Elements ◽

Numerical Homogenization ◽

Single Plate ◽

Energy Equivalence ◽

Numerical Tools ◽

Simplified Procedures ◽

Excellent Tool

The need for quick and easy deflection calculations of various prefabricated slabs causes simplified procedures and numerical tools to be used more often. Modelling of full 3D finite element (FE) geometry of such plates is not only uneconomical but often requires the use of complex software and advanced numerical knowledge. Therefore, numerical homogenization is an excellent tool, which can be easily employed to simplify a model, especially when accurate modelling is not necessary. Homogenization allows for simplifying a computational model and replacing a complicated composite structure with a homogeneous plate. Here, a numerical homogenization method based on strain energy equivalence is derived. Based on the method proposed, the structure of the prefabricated concrete slabs reinforced with steel spatial trusses is homogenized to a single plate element with an effective stiffness. There is a complete equivalence between the full 3D FE model built with solid elements combined with truss structural elements and the simplified homogenized plate FE model. The method allows for the correct homogenization of any complex composite structures made of both solid and structural elements, without the need to perform advanced numerical analyses. The only requirement is a correctly formulated stiffness matrix of a representative volume element (RVE) and appropriate formulation of the transformation between kinematic constrains on the RVE boundary and generalized strains.

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Solid-Truss to Shell Numerical Homogenization of Prefabricated Composite Slabs

10.20944/preprints202105.0681.v1 ◽

2021 ◽

Author(s):

Natalia Staszak ◽

Tomasz Garbowski ◽

Anna Szymczak-Graczyk

Keyword(s):

Composite Structures ◽

Homogenization Method ◽

Fe Model ◽

Structural Elements ◽

Numerical Homogenization ◽

Single Plate ◽

Energy Equivalence ◽

Numerical Tools ◽

Simplified Procedures ◽

Excellent Tool

The need for quick and easy deflection calculations of various prefabricated slabs causes that simplified procedures and numerical tools are used more and more often. Modelling of full 3D finite element (FE) geometry of such plates is not only uneconomical but often requires the use of complex software and advanced numerical knowledge. Therefore, numerical homogenization is an excellent tool, which can be easily employed to simplify a model, especially when accurate modelling is not necessary. Homogenization allows for simplifying a computational model and replacing a complicated composite structure with a homogeneous plate. Here, a numerical homogenization method based on strain energy equivalence is derived. Using the method proposed, the structure of the prefabricated concrete slabs reinforced with steel spatial trusses is homogenized to a single plate element with an effective stiffness. There is a complete equivalence between the full 3D FE model built with solid elements combined with truss structural elements and the simplified homogenized plate FE model. The method allows for the correct homogenization of any complex composite structures made of both solid and structural elements, without the need to perform advanced numerical analyses. The only requirement is a correctly formulated stiffness matrix of a representative volume element (RVE) and appropriate formulation of the transformation between kinematic constrains on RVE boundary and generalized strains.

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In Situ microscopy of the anodic etching of silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137537 ◽

1995 ◽

Vol 53 ◽

pp. 232-233

Author(s):

Frances M. Ross ◽

Peter C. Searson

Keyword(s):

Composite Structures ◽

High Surface ◽

High Surface Area ◽

Chemical Properties ◽

Selective Etching ◽

Silicon On Insulator ◽

Second Phase ◽

Porous Layers ◽

New Class ◽

Porous Semiconductors

Porous semiconductors represent a relatively new class of materials formed by the selective etching of a single or polycrystalline substrate. Although porous silicon has received considerable attention due to its novel optical properties1, porous layers can be formed in other semiconductors such as GaAs and GaP. These materials are characterised by very high surface area and by electrical, optical and chemical properties that may differ considerably from bulk. The properties depend on the pore morphology, which can be controlled by adjusting the processing conditions and the dopant concentration. A number of novel structures can be fabricated using selective etching. For example, self-supporting membranes can be made by growing pores through a wafer, films with modulated pore structure can be fabricated by varying the applied potential during growth, composite structures can be prepared by depositing a second phase into the pores and silicon-on-insulator structures can be formed by oxidising a buried porous layer. In all these applications the ability to grow nanostructures controllably is critical.

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