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.

scholarly journals NUMERICAL SIMULATION ANDCONSTRUCTAL DESIGN APPLIED TO THE STUDY OF ELASTIC BUCKLING IN THIN STEEL PLATES WITH OBLONG PERFORATIONS

2018 ◽  
Vol 8 (20) ◽  
Author(s):  
Emilio Gabriel Gonçalves Folzke ◽  
Thiago Da Silveira ◽  
João Paulo Silva Lima ◽  
Luiz Alberto Oliveira Rocha ◽  
Elizaldo Domingues Dos Santos ◽  
...  
Keyword(s):  
Critical Load ◽  
Volume Fraction ◽  
Design Method ◽  
Steel Plates ◽  
Constructal Theory ◽  
Elastic Buckling ◽  
The Finite Element Method ◽  
Perforated Plates ◽  
Constructal Design ◽  
Thin Steel

ABSTRACTBuckling is an instability phenomenon that can happen when a slender plate is subjected to axial compression loads. In addition, perforated plates are often necessary in the engineering field. Throughout this article, the Constructal Design Method, which is based on the Constructal Theory, has been used to evaluate the influence of the hole on thin steel plates under elastic buckling. For that, the different types of holes analyzed were both transversal and longitudinal oblong. They were all placed in the center of the plate. The geometry of the hole varied according to the degree of freedom H0/L0, which relates the dimensions of each type of different hole. The size of the perforation are varied by means the hole volume fraction (f) parameter, that represents the relation between the volume of the hole and the total volume of the plate (without hole). The main goal is to achieve the greatest critical load for the perforated plates. To do so, the ANSYS software, based on the Finite Element Method (FEM), has been used to numerically analyze the elastic buckling in each case. It has been observed the importance of the geometry when seeking superior performances: through a simple fluctuation of the geometry of the hole, once the volume fraction was kept constant, it was possible to achieve a significant increase on the critical loads. Key words: Buckling; Computational Modeling; Critical Load; Constructal Design.

Constructal Design Associated to Genetic Algorithm of Asymmetric V-Shaped Pathways

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Emanuel da S. D. Estrada ◽  
Tadeu M. Fagundes ◽  
Liércio A. Isoldi ◽  
Elizaldo D. dos Santos ◽  
Gongnan Xie ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Thermal Resistance ◽  
Degrees Of Freedom ◽  
Volume Fraction ◽  
Geometric Optimization ◽  
Heat Sinks ◽  
Heat Generation Rate ◽  
Conductive Materials ◽  
Constructal Design ◽  
Optimal Shapes

This work relies on constructal design to perform the geometric optimization of the V-shaped pathways of highly conductive materials (inserts) that remove a constant heat generation rate from a body and deliver it to isothermal heat sinks. It is shown numerically that the global thermal resistance of the V-shaped pathway can be minimized by geometric optimization subject to total volume and V-shaped pathways material constraints. Constructal design and genetic algorithm (GA) optimization showed the emergence of an optimal architecture that minimizes the global thermal resistance: an optimal external shape for the assembly of pathways and optimal geometry features for the V-shaped pathway. Parametric study was performed to show the behavior of the minimized global thermal resistance as function of the volume fraction of the V-shaped pathways. First achieved results for ϕ = 0.3 indicated that when freedom is given to the geometry, the thermal performance is improved. Afterward, the employment of GA with constructal design allowed the achievement of the optimal shapes of V-shaped pathways for different volume fractions (0.2 ≤ ϕ ≤ 0.4). It was not realized the occurrence of one universal optimal shape for the several values of ϕ investigated, i.e., the optimal design was dependent on the degrees of freedom and the parameter ϕ and it is reached according to constructal principle of optimal distribution of imperfections.

scholarly journals Study About Buckling Phenomenon in Perforated Thin Steel Plates Employing Computational Modeling and Constructal Design Method

2016 ◽  
Vol 13 (10) ◽  
pp. 1912-1936 ◽  
Author(s):  
Daniel Helbig ◽  
Caio Cesar Cardoso da Silva ◽  
Mauro de Vasconcellos Real ◽  
Elizaldo Domingues dos Santos ◽  
Liércio André Isoldi ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Design Method ◽  
Steel Plates ◽  
Constructal Design ◽  
Thin Steel

Geometric evaluation of steel plates subjected to uniform transverse load with rectangular or trapezoidal stiffeners by means constructal design method

2020 ◽  
Vol 3 (2) ◽  
pp. 190
Author(s):  
Vinícius Torres Pinto ◽  
Marcelo Langhinrichs Cunha ◽  
Kauê Louro Martins ◽  
Luiz Alberto Oliveira Rocha ◽  
Mauro De Vasconcellos Real ◽  
...  
Keyword(s):  
Design Method ◽  
Steel Plates ◽  
Transverse Load ◽  
Constructal Design

Numerical study of the elasto-plastic buckling in perforated thin steel plates using the constructal design method

2018 ◽  
Author(s):  
Daniel Helbig ◽  
◽  
Marcelo Langhinrichs Cunha ◽  
Caio Cesar Cardoso da Silva ◽  
Elizaldo Domingues dos Santos ◽  
...  
Keyword(s):  
Numerical Study ◽  
Design Method ◽  
Steel Plates ◽  
Plastic Buckling ◽  
Constructal Design ◽  
Thin Steel

Constructal Design of Double-T Shaped Cavity with Stochastic Methods Luus-Jaakola and Simulated Annealing

2017 ◽  
Vol 370 ◽  
pp. 152-161 ◽  
Author(s):  
Gill Velleda Gonzales ◽  
Elizaldo Domingues dos Santos ◽  
Liércio André Isoldi ◽  
Luiz Alberto Oliveira Rocha ◽  
Antônio José da Silva Neto ◽  
...  
Keyword(s):  
Simulated Annealing ◽  
Degrees Of Freedom ◽  
Hybrid Methods ◽  
Transfer Problem ◽  
Geometric Optimization ◽  
Stochastic Methods ◽  
Statistical Tool ◽  
Constructal Design ◽  
Cooling Schedule ◽  
Complete Optimization

In this paper it is proposed a comparison between two stochastic methods, Simulated Annealing and Luus-Jaakola algorithms, applied in association with Constructal Design to the geometric optimization of a heat transfer problem. The problem consists in a solid body with an internal uniform heat generation, which is cooled by an intruded cavity that is maintained at a minimal temperature. The other surfaces are kept as adiabatic. The objective is to minimize the maximum excess of temperature (θmax) in the solid domain through geometric optimization of the isothermal double-T shaped cavity. The problem geometry has five degrees of freedom, but in this study four degrees of freedom are evaluated, keeping fixed the ratio H/L (ratio between the height and length of the solid domain) as well as the cavity constraints. The search for the optimal geometry is performed by Simulated Annealing and the Luus-Jaakola algorithm with different configurations or set of main parameters. Each algorithm is executed twenty times and the results for θmax, and corresponding geometry ratios, are recorded. Results of two heuristics are compared in order to select the best method for future studies about the complete optimization of the cavity, as well as, the evaluation of constraints over the thermal performance of the problem. The method employed to compare and rank the different versions of the two algorithms is a statistical tool called multi-comparison of Kruskal-Wallis. With this statistical method it is possible to classify the algorithms in three main groups. Results showed that the Simulated Annealing with hybrid parameters of Cooling Schedule (BoltzExp and ConstExp2) and traditional ones (Exponential) led to the highest probability to find the global optimal shape, while the results obtained with the Luus-Jaakola algorithm reached to several local points of minimum far from the best shape for all versions of the algorithm studied here. However, the Luus-Jaakola algorithm led to the lowest magnitude of maximum excess of temperature, showing that the implementation of hybrid methods of optimization can be an interesting strategy for evaluation of this kind of problem.

Analysis of Geometric Variation of Three Degrees of Freedom through the Constructal Design Method for a Oscillating Water Column Device with Double Hidropneumatic Chamber

2019 ◽  
Vol 396 ◽  
pp. 22-31
Author(s):  
Yuri T.B. Lima ◽  
Mateus das Neves Gomes ◽  
Camila F. Cardozo ◽  
Liércio André Isoldi ◽  
Elizaldo D. Santos ◽  
...  
Keyword(s):  
Water Column ◽  
Degrees Of Freedom ◽  
Numerical Study ◽  
Design Method ◽  
Geometric Optimization ◽  
Oscillating Water Column ◽  
Constructal Design ◽  
Wave Energy Converters ◽  
Volume Method ◽  
Geometric Variation

This paper presents a biphasic two-dimensional numerical study of sea wave energy converters with operating principle being Oscillating Water Column (CAO) devices with two couples chambers. For the study of the geometric optimization, the Constructal Design method is applied in association with the exhaustive search method to determine the geometric arrangement that leads to the greatest hydropneumatic power available. The objective function is the maximization of hydropneumatic power converted by the device. The constraints of the problem are the inflow volumes of the hydropneumatic chamber (VE1, VE2), the total volumes (VT1, VT2) and the thicknesses of the device columns (e1, e3). The degrees of freedom analyzed were H1/L1(ratio between height and length of the hydropneumatic chamber of the first device), H2/L2 (ratio between height and length of the hydropneumatic chamber of the second device), H2 (height of the column dividing the two devices) and e2 (thickness of the column dividing the devices). In the present work the degree of freedom H6 (depth of immersion of the device) is kept constant and equal to H6 = 9.86 m. The Finite Volume Method (FVM) was used in the numerical solution of the equations employed. For the treatment of the interaction between the air and water phases, the Volume of Fluid (VOF) method was applied. The results show that the maximum hydropneumatic power available was 5715.2 W obtained for degrees of freedom H1/L1 = H2/L2 = 0.2613 and e2 = 2.22 m. The case of lower performance has a power value equal to 4818.5 W with degrees of freedom equal to H1/L1 = H2/L2 = 0.2613 and e2 = 0.1 m.

scholarly journals GEOMETRIC OPTIMIZATION OF “+”-SHAPED CAVITY USING CONSTRUCTAL THEORY

2017 ◽  
Vol 16 (1) ◽  
pp. 75
Author(s):  
P. A. Avendaño ◽  
J. A. Souza ◽  
D. F. Adamatti ◽  
E. D. dos Santos
Keyword(s):  
Solid Body ◽  
Degrees Of Freedom ◽  
Internal Heat ◽  
Thermal Conditions ◽  
Geometric Optimization ◽  
Optimal Performance ◽  
Constructal Theory ◽  
Maximum Temperature ◽  
Constructal Design ◽  
Better Than

In this work it is applied the Constructal Theory for the study of the geometry of an “+”-shaped isothermal cavity inserted in a conductive solid body. Main goal is to minimize the maximum temperature in the solid. The total volume of the solid and the total volume of the cavity are kept fixed while the dimensions of the cavity geometry vary according to constraints and degrees of freedom defined by the Constructal Design. The solid body has internal heat generation and its external surfaces are insulated. Cavity walls are isothermal with constant temperature Tmin. Obtained results indicate that the optimal performance of “+”-shape cavity is 37.2% better that the optimal performance of “C”-shape cavity and 10.8% better than the “T”-shaped cavity for the same thermal conditions.

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