scholarly journals Solid-Truss to Shell Numerical Homogenization of Prefabricated Composite Slabs

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.

scholarly journals Solid Truss to Shell Numerical Homogenization of Prefabricated Composite Slabs

Materials ◽  
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.

scholarly journals Numerical Homogenization of Multi-Layered Corrugated Cardboard with Creasing or Perforation

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3786
Author(s):  
Tomasz Garbowski ◽  
Anna Knitter-Piątkowska ◽  
Damian Mrówczyński
Keyword(s):  
Computational Models ◽  
Load Capacity ◽  
Torsional Stiffness ◽  
Numerical Homogenization ◽  
Corrugated Board ◽  
3D Geometry ◽  
Corrugated Cardboard ◽  
Numerical Tools ◽  
Packaging Industry ◽  
Theoretical Considerations

The corrugated board packaging industry is increasingly using advanced numerical tools to design and estimate the load capacity of its products. This is why numerical analyses are becoming a common standard in this branch of manufacturing. Such trends cause either the use of advanced computational models that take into account the full 3D geometry of the flat and wavy layers of corrugated board, or the use of homogenization techniques to simplify the numerical model. The article presents theoretical considerations that extend the numerical homogenization technique already presented in our previous work. The proposed here homogenization procedure also takes into account the creasing and/or perforation of corrugated board (i.e., processes that undoubtedly weaken the stiffness and strength of the corrugated board locally). However, it is not always easy to estimate how exactly these processes affect the bending or torsional stiffness. What is known for sure is that the degradation of stiffness depends, among other things, on the type of cut, its shape, the depth of creasing as well as their position or direction in relation to the corrugation direction. The method proposed here can be successfully applied to model smeared degradation in a finite element or to define degraded interface stiffnesses on a crease line or a perforation line.

Stress analysis of finite orthotropic composite containing an elliptical hole

2021 ◽  
pp. 002199832110507
Author(s):  
Narin S. Fatima ◽  
Robert E. Rowlands
Keyword(s):  
Composite Structures ◽  
Elliptical Hole ◽  
External Loading ◽  
Finite Geometries ◽  
Orthotropic Composites ◽  
Numerical Tools ◽  
Design Type ◽  
Measured Displacement ◽  
Type Information ◽  
Important Design

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.

scholarly journals Condensation method in practical modal analysis of hull vibration with application of 3D FE model

2019 ◽  
pp. 162-169
Author(s):  
Valeriy Sutyrin
Keyword(s):  
Modal Analysis ◽  
Three Dimensional ◽  
Element Model ◽  
Fe Model ◽  
Structural Elements ◽  
Natural Vibrations ◽  
Condensation Method ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Analytical Approaches

This paper gives modal analysis results for mid-body of a refrigerator carrier ship by means of combined three-dimensional finite-element model with 1.5 million DOF. The study estimates the error of modal analysis for the ship structure if its boundary conditions are specified in advance, i.e. approximately, as well as analyses the gain in time offered by structuring the analytical model as per reduction (condensation) method. Analytical approaches thus transformed can be successfully applied in filtering lower frequencies and modes of natural vibrations for structural elements and joints of hull in the direct vicinity of exciting force application points.

Timber-Concrete Composite Structural Elements

2021 ◽  
Author(s):  
Anita Ogrin ◽  
Tomaž Hozjan
Keyword(s):  
Tensile Strength ◽  
Composite Structures ◽  
Wood Products ◽  
Structural Elements ◽  
Long Span Bridges ◽  
Long Span ◽  
Bending Load ◽  
Engineered Wood Products ◽  
Floor Systems ◽  
Connection Type

Timber-concrete composites are interesting engineered wood products usually used for structural elements, which are mainly subjected to bending load; from simple floor systems to long-span bridges. This way, the advantage can be taken of timber tensile strength and concrete compression strength. The chapter begins with an introduction of various types of timber-concrete composite structural elements regarding type of the element, connection type and types of timber and concrete. Next, specific characteristics and advantages of timber-concrete composite structural elements are thoroughly discussed from viewpoints of engineering, architecture, builders and ecology. Furthermore, basic mechanical principles of timber-concrete composite structural elements are presented and some design methods are briefly described. Finally, worldwide inclusion of timber-concrete composite structures in currently applicable standards is discussed.

scholarly journals Application of Modal-Displacement Based Design Method to Multi-Story Timber Blockhaus Structures

2020 ◽  
Vol 10 (11) ◽  
pp. 3889
Author(s):  
Martina Sciomenta ◽  
Vincenzo Rinaldi ◽  
Chiara Bedon ◽  
Massimo Fragiacomo
Keyword(s):  
Design Method ◽  
Fe Model ◽  
Structural Elements ◽  
Base Shear ◽  
Shear Loads ◽  
Story Drift ◽  
Displacement Based ◽  
Technical Interest ◽  
Wooden Structures

Structures under seismic excitation undergo different inter-story drift levels that can be associated to damage of both structural and non-structural elements, and thus to the expected losses. The Modal-Displacement Based Design (DBD) procedure, in this regard, has been developed to fix major issues of Force Based Design (FBD) approaches, thus to design multi-story buildings in which the inter-story drift can allow one to control damage mechanisms. In this paper, the conventional Modal-DBD methodology is applied to multi-story timber buildings constructed using the Blockhaus technology. Given their intrinsic geometrical and mechanical features (i.e., stacking of logs, door/window openings, gaps and friction mechanisms, etc.), dedicated methods of analysis are required for them, compared to other wooden structures. A three-story case-study Blockhaus system of technical interest is thus presented for the assessment of Modal-DBD calculation steps. As shown, special care must be spent for the selection of convenient inter-story drift limits that in general should reflect the characteristics of the examined structural typology. The backbone parameters are thus collected for each shear-wall composing the 3D Blockhaus building, based on refined Finite Element (FE) analyses of separate log-walls. The overall results of the Modal-DBD process are thus finally assessed by means of a Push-Over (PO) analysis, carried out on a simplified 3D FE model of the examined multi-story structure. The comparison of FE predictions, as shown, demonstrates that reliable estimates can be obtained when the Modal-DBD procedure is applied to timber Blockhaus systems. In particular, base shear loads can be estimated with good accuracy, while the corresponding top displacements are slightly overestimated (with up to +10%–14% the expected values, for the collapse prevention performance level).

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

2019 ◽  
Author(s):  
Alexandre Imperiale ◽  
Edouard Demaldent ◽  
Nicolas Leymarie ◽  
Sylvain Chatillon ◽  
Pierre Calmon
Keyword(s):  
Ultrasonic Testing ◽  
Composite Structures ◽  
Numerical Tools

Structural-Acoustic Optimization of Sandwich Panels

2005 ◽  
Author(s):  
Francesco Franco ◽  
Kenneth A. Cunefare ◽  
Massimo Ruzzene
Keyword(s):  
Numerical Optimization ◽  
Composite Structures ◽  
Gradient Methods ◽  
Sandwich Panels ◽  
Relative Importance ◽  
Structural Elements ◽  
Acoustic Response ◽  
The Core ◽  
Design Flexibility ◽  
The Face

Sandwich panels, comprising face sheets enclosing a core, are increasingly common structural elements in a variety of applications, including aircraft fuselages and flight surfaces, vehicle panels, lightweight enclosures, and bulkheads. The design flexibility associated with such composite structures provides significant opportunities for tailoring the structure to the load and dynamic response requirements for the particular application. Design flexibility encompasses the details of the face sheets and the core. This paper deals with the numerical optimization of different sandwich configurations for the purposes of achieving reduced structural acoustic response. Laminated face sheets and core geometries, comprising honeycomb and truss-like structures, are considered. The relative importance of the mass and stiffening properties of the core and face sheets are discussed. The optimization work is carried out using commercial codes. Benefits and limits of using an optimization algorithm based on gradient methods are highlighted.

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