scholarly journals Numerical simulation and constructal design applied to plates with different heights of traverse and longitudinal stiffeners

2021 ◽  
pp. 221-238
Author(s):  
Carolina Martins Nogueira ◽  
Vinícius Torres Pinto ◽  
Luiz Alberto Oliveira Rocha ◽  
Elizaldo Domingues dos Santos ◽  
Liércio André Isoldi
Keyword(s):  
Computational Models ◽  
Design Method ◽  
Geometric Analysis ◽  
Stiffened Plates ◽  
Constructal Design ◽  
Longitudinal Stiffeners ◽  
Out Of Plane ◽  
Material Volume ◽  
Geometric Arrangements ◽  
Reference Plate

Martins Nogueira, Vinícius Torres Pinto, Luiz Alberto Oliveira Rocha, Elizaldo Domingues dos Santos and Liércio André Isoldi Right click to download the paper PDF (550K) Abstract: This study applied the Constructal Design Method (CDM) associated with the Finite Element Method (FEM) through computational models to perform a geometric analysis on rectangular stiffened plates of steel subjected to a uniform transverse loading, in order to minimize its maximum and central out-of-plane deflections. Considering a non-stiffened plate as reference and maintaining the total volume of steel constant, a portion of material volume deducted from its thickness was transformed into stiffeners through the ϕ parameter, which represents the ratio between the material volume of the stiffeners and the reference plate. Adopting ϕ = 0.30, 27 geometric arrangements of stiffened plates were established, being 9 arrangements for each 3 different stiffeners' thicknesses adopted: ts = 6.35 mm, ts = 12.70 mm and ts = 25.40 mm. For each ts value, the number of longitudinal (Nls) and transverse (Nts) stiffeners were varied from 2 to 4. Thus, in each plate arrangement configured, the influence of the ratio between the height of the transverse and longitudinal stiffeners (hts/hls) was analyzed, taking into account the values 0.50; 0.75; 1.00; 1.25; 1.50; 1.75 and 2.00, regarding to the maximum and central deflections. The results have shown that transforming a portion of steel from a non-stiffened reference plate into stiffeners can reduce the maximum and central deflections by more than 90%. Moreover, it was observed that to reduce the deflections it is more effective consider hts > hls, once the ratio hts/hls = 2.00 was the one that led to the better mechanical behavior among the analyzed cases.

scholarly journals Geometric Evaluation of Stiffened Steel Plates Subjected to Transverse Loading for Naval and Offshore Applications

2019 ◽  
Vol 7 (1) ◽  
pp. 7 ◽  
Author(s):  
João Pedro T. P. De Queiroz ◽  
Marcelo L. Cunha ◽  
Ana Pavlovic ◽  
Luiz Alberto O. Rocha ◽  
Elizaldo D. Dos Santos ◽  
...  
Keyword(s):  
Design Method ◽  
Steel Plates ◽  
Stiffened Plates ◽  
Geometrical Configuration ◽  
Ansys Software ◽  
Search Technique ◽  
Constructal Design ◽  
Longitudinal Stiffeners ◽  
Stiffened Steel ◽  
Reference Plate

This work searched for the optimal geometrical configuration of simply supported stiffened plates subjected to a transverse and uniformly distributed load. From a non-stiffened reference plate, different geometrical configurations of stiffened plates, with the same volume as the reference plate, were defined through the constructal design method. Thus, applying the exhaustive search technique and using the ANSYS software, the mechanical behaviors of all the suggested stiffened plates were compared to each other to find the geometrical configuration that provided the minimum deflection in the plate’s center when subjected to this loading. The optimum geometrical configuration of stiffeners is presented at the end of this work, allowing a reduction of 98.57% for the central deflection of the stiffened plate if compared to the reference plate. Furthermore, power equations were adjusted to describe the deflections for each combination of longitudinal and transverse stiffeners as a function of the ratio between the height and the thickness of the stiffeners. Finally, a unique equation for determining the central deflections of the studied stiffened plates based only on the number of longitudinal stiffeners without significantly losing accuracy has been proposed.

scholarly journals Numerical analysis of stiffened plates subjected to transverse uniform load through the constructal design method

2022 ◽  
Vol 10 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Vinícius Torres Pinto ◽  
Luiz Alberto Oliveira Rocha ◽  
Elizaldo Domingues dos Santos ◽  
Liércio André Isoldi
Keyword(s):  
High Performance ◽  
Design Method ◽  
Material Constant ◽  
Stiffened Plates ◽  
The Finite Element Method ◽  
Uniform Load ◽  
Constructal Design ◽  
Geometric Configurations ◽  
Out Of Plane ◽  
Do So

When it comes to engineering, high performance is always a desired goal. In this context, regarding stiffened plates, the search for better geometric configurations able to minimize the out-of-plane displacements become interesting. So, this study aimed to analyze several stiffened plates defined by the Constructal Design Method (CDM) and solved through the Finite Element Method (FEM) using the ANSYS® software. After that, these plates are compared among each other through the Exhaustive Search (ES) technique. To do so, a non-stiffened rectangular plate was adopted as reference. Then, a portion of its steel volume was converted into stiffeners through the ϕ parameter, which represents the ratio between the volume of the stiffeners and the total volume of the reference plate. Taking into consideration the value of ϕ = 0.3, 75 different stiffened plates arrangements were proposed: 25 with rectangular stiffeners oriented at 0°; 25 with rectangular stiffeners oriented at 45° and 25 with trapezoidal stiffeners oriented at 0°. Maintaining the total volume of material constant, it was investigated the geometry influence on the maximum deflection of these stiffened plates. The results have shown trapezoidal stiffeners oriented at 0° are more effective to reduce the maximum deflections than rectangular stiffeners also oriented at 0°. It was also observed that rectangular stiffeners oriented at 45° presented the smallest maximum deflections for the majority of the analyzed cases, when compared to the trapezoidal and rectangular stiffeners oriented at 0°.

scholarly journals ANALYSIS THROUGH CONSTRUCTAL DESIGN OF THE INFLUENCE OF SPACING BETWEEN STIFFENERS IN THE DEFLECTION OF PLATES

2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Milton Cesar Bastos Portela Junior ◽  
Vinícius Torres Pinto ◽  
Luiz Alberto Oliveira Rocha ◽  
Elizaldo Domingues Dos Santos ◽  
Liércio André Isoldi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Design Method ◽  
Stiffened Plates ◽  
Stiffened Plate ◽  
The Finite Element Method ◽  
Volumetric Fraction ◽  
Constructal Design ◽  
Fixed Volume ◽  
Reference Plate

Using the Finite Element Method (FEM), stiffened plates arrangements defined by the application of the Constructal Design Method (CDM) were analyzed. So that, through an Exhaustive Search (ES), different spacing between the stiffeners were tested regarding the central and maximum deflections. Starting from a non-stiffened plate with a fixed volume, a portion of its material was completely removed from its thickness and transformed into stiffeners considering the volumetric fraction 𝜙 = 0.5. It were established 4 arrangements: P(2,2), P(2,3), P(3,2) and P(3,3), varying for each one, the spacing between the stiffeners, as well as the parameter hs/ts (ratio between height and thickness of stiffeners). The results showed that stiffeners equally spaced in the longitudinal and transverse directions with higher ratios hs/ts are more effective, being able to reduce the central and maximum deflections by more than 95% compared to the non-stiffened reference plate.

scholarly journals Constructal design method dealing with stiffened plates and symmetry boundaries

2020 ◽  
Vol 10 (5) ◽  
pp. 366-376
Author(s):  
Rodrigo R. Amaral ◽  
Grégori S. Troina ◽  
Cristiano Fragassa ◽  
Ana Pavlovic ◽  
Marcelo L. Cunha ◽  
...  
Keyword(s):  
Design Method ◽  
Stiffened Plates ◽  
Constructal Design

Verification of a genetic algorithm for the optimization of stiffened plates through the constructal design method

2019 ◽  
Author(s):  
Marcelo Langhinrichs Cunha ◽  
◽  
Emanuel da Silva Diaz Estrada ◽  
Grégori da Silva Troina ◽  
Elizaldo Domingues dos Santos ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Design Method ◽  
Stiffened Plates ◽  
Constructal Design

scholarly journals Computational Modeling and Constructal Design Theory Applied to the Geometric Optimization of Thin Steel Plates with Stiffeners Subjected to Uniform Transverse Load

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 220 ◽  
Author(s):  
Grégori Troina ◽  
Marcelo Cunha ◽  
Vinícius Pinto ◽  
Luiz Rocha ◽  
Elizaldo dos Santos ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Design Theory ◽  
Degrees Of Freedom ◽  
Volume Fraction ◽  
Geometric Optimization ◽  
Steel Plates ◽  
Transverse Load ◽  
Constructal Design ◽  
Thin Steel ◽  
Reference Plate

Stiffened thin steel plates are structures widely employed in aeronautical, civil, naval, and offshore engineering. Considering a practical application where a transverse uniform load acts on a simply supported stiffened steel plate, an approach associating computational modeling, Constructal Design method, and Exhaustive Search technique was employed aiming to minimize the central deflections of these plates. To do so, a non-stiffened plate was adopted as reference from which all studied stiffened plate’s geometries were originated by the transformation of a certain amount of steel of its thickness into longitudinal and transverse stiffeners. Different values for the stiffeners volume fraction (φ) were analyzed, representing the ratio between the volume of the stiffeners’ material and the total volume of the reference plate. Besides, the number of longitudinal (Nls) and transverse (Nts) stiffeners and the aspect ratio of stiffeners shape (hs/ts, being hs and ts, respectively, the height and thickness of stiffeners) were considered as degrees of freedom. The optimized plates were determined for all studied φ values and showed a deflection reduction of over 90% in comparison with the reference plate. Lastly, the influence of the φ parameter regarding the optimized plates was evaluated defining a configuration with the best structural performance among all analyzed cases.

Numerical and Geometrical Analysis of the Onshore Oscillating Water Column Wave Energy with a Ramp

2021 ◽  
Vol 412 ◽  
pp. 11-26
Author(s):  
Marla Rodrigues Oliveira ◽  
Elizaldo Domingues Santos ◽  
Liércio André Isoldi ◽  
Luiz Alberto Oliveira Rocha ◽  
Mateus das Neves Gomes
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Degrees Of Freedom ◽  
Design Method ◽  
Geometric Analysis ◽  
Relative Difference ◽  
Front Wall ◽  
Multiphase Model ◽  
Oscillating Water Column ◽  
Worst Case

This study is about a two-dimensional numerical analysis of the influence of a ramp in front on an oscillating water column wave energy converter (OWC-WEC). The main purpose was to evaluate, numerically and geometrically, the effect of using a ramp variation in relation to the frontal wall on the hydropneumatic power of the OWC-WEC. The constructal design method was applied for geometric analysis. The problem had a geometric constraint: the area of the ramp (A2) and two degrees of freedom: H2 / L2 (ratio of the height and length of the ramp) and L4 (the distance of the ramp concerning the OWC-WEC front wall). In numerical simulations, the equations of conservation of mass, momentum, and an equation for the transport of volumetric fraction were solved using the finite volume method (FVM). The multiphase model volume of fluid (VOF) was applied for the air-water interaction. Thus, the increase in the H2/L2 ratio resulted in a decrease of the root mean square (RMS) of the available hydropneumatic power (Phyd). By varying the distance L4, the better case was = 6 m and / = 0.025 and the worst case was = 1 m and / = 0.2. The relative difference between the better RMS Phyd = 150.7957 W and the worst Phyd = 73.1164 W reached up to a hundred and six percent.

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