Daniel Helbig - Academia.edu (original) (raw)
Papers by Daniel Helbig
Many elements in engineering are formed by thin plates. Hulls and decks of ships are examples of ... more Many elements in engineering are formed by thin plates. Hulls and decks of ships are examples of application. These elements can have holes that serve as inspection port, access or even to weight reduction. The presence of holes causes a redistribution of the membrane stresses in the plate, significantly altering their stability. In this paper the Bejan’s Constructal Theory was employed to discover the best geometry of thin perforated plates submitted to elastic buckling phenomenon. To study this behavior simply supported rectangular plates with a centered elliptical perforation were analyzed. The purpose was to obtain the optimal geometry which maximizes the critical buckling load. For this, the degrees of freedom H/L (ratio between width and length of the plate) and H0/L0 (ratio between the characteristic dimensions of the hole) were varied. Moreover, different values of hole volume fraction ϕ (ratio between the perforation volume and the massive plate volume) were also investigat...
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2019
Slenderness is a remarkable geometrical characteristic of thin steel plates. When a slender plate... more Slenderness is a remarkable geometrical characteristic of thin steel plates. When a slender plate is subjected to an axial compression loading, a mechanical behavior called buckling can occur, causing an out-of-plane displacement. This instability phenomenon can be divided into elastic buckling (linear) and elasto-plastic buckling (nonlinear), depending on dimensional, constructive, or operational aspects. Moreover, in several practical situations, it is necessary to provide holes on thin steel plates, causing stress redistribution and changes in its buckling behavior. The present work purposes a buckling study in square and rectangular plates, simply supported, with two different centered perforations types: longitudinal hexagonal and transverse hexagonal. Numerical simulation, using the ANSYS ® software, was employed to determine the critical buckling load and the ultimate buckling load of the plates. The constructal design method was applied, allowing evaluating the variation effect of the degree of freedom H 0 /L 0 (being H 0 the width and L 0 the length of the perforation) on the plate's mechanical buckling behavior. The hole volume fraction (ϕ) was another considered parameter, corresponding to cutouts of 10%, 15%, 20%, and 25% of the total plate volume. The results showed the direct influence of the H 0 /L 0 ratio on the buckling type, allowing the definition of a buckling stress limit curve for each cutout type and hole volume fraction. Besides, the constructal design method, associated with the exhaustive search technique, enabled to define the optimized geometric configuration for each hole type that conducted the plate to a maximized mechanical performance.
Proceedings of the XXXVI Iberian Latin American Congress on Computational Methods in Engineering, 2015
Proceedings of the 23rd ABCM International Congress of Mechanical Engineering, 2015
Scientia Plena, 2019
As evoluções no desenvolvimento de materiais compósitos possibilitam cada vez mais o seu uso. Alg... more As evoluções no desenvolvimento de materiais compósitos possibilitam cada vez mais o seu uso. Algumas das ferramentas que contribuíram para essa evolução foram o Método dos Elementos Finitos e as ferramentas de simulação numérica, pois possibilitaram a avaliação do comportamento e da resistência desses materiais ainda na fase de projeto. Esses métodos permitem ao pesquisador conhecer de maneira muito próxima o comportamento dos elementos e das estruturas, porém, como são métodos aproximados, não se pode esperar que os resultados fossem exatamente iguais aos reais. Este trabalho procura analisar o comportamento mecânico de placas finas de materiais compósitos laminados reforçados por fibras submetidas a esforços de flexão, comparando-as com o de uma placa de aço. Para a modelagem computacional do problema utilizouse o software Abaqus 2017 Student Version® cuja base está fundamentada no Método dos Elementos Finitos. Na sequência, busca-se comparar os resultados obtidos neste trabalho ...
Steel plates are used in a great variety of engineering applications, such as deck and bottom of ... more Steel plates are used in a great variety of engineering applications, such as deck and bottom of ship structures, and platforms of offshore structures. Cutouts are often provided in plate elements for inspection, maintenance, and service purposes. So, the design of shape and size of these holes is significant. Usually these plates are subjected to axial compressive forces which make them prone to instability or buckling. If the plate is slender, the buckling is elastic. However, if the plate is sturdy, it buckles in the plastic range causing the so-called inelastic (or elasto-plastic) buckling.Therefore, the goal of this work is to obtain the optimal geometry which maximizes the buckling load for steel plates with a centered elliptical perforation when subjected to linear and nonlinear buckling phenomenon by means of Constructal Design. To do so, numerical models were developed in ANSYS software to evaluate the elastic and elasto-plastic buckling loads of simply supported and uniaxi...
Scientia Plena, 2015
Placas finas de aço são elementos estruturais muito utilizados em diversas aplicações de engenhar... more Placas finas de aço são elementos estruturais muito utilizados em diversas aplicações de engenharia, como em plataformas offshore, pontes, navios, aviões e automóveis. Porém, em algumas situações específicas as placas podem sofrer flambagem térmica, que é uma deflexão lateral causada simplesmente por um aumento de temperatura (variação crítica de temperatura). Este artigo utilizou um modelo computacional desenvolvido no software ANSYS, que é baseado no Método dos Elementos Finitos (MEF), para tratar o problema da flambagem térmica em placas. O modelo numérico foi verificado através da comparação de seus resultados com a solução analítica do problema. Foram analisadas placas com diferentes relações de…
Latin American Journal of Solids and Structures, 2016
Perforated steel thin plates are commonly used in structural engineering. Due to their geometric ... more Perforated steel thin plates are commonly used in structural engineering. Due to their geometric characteristics, these panels can suffer the undesired buckling phenomenon. In this context, the present work associates the computational modeling and the constructal design method to evaluate the influence of the geometric configuration in the plate buckling behavior, using the exhaustive search method to determine which geometries conduct to superior mechanical behavior. To do so, numerical models are employed to solve elastic and elasto-plastic buckling of plates having a centered perforation. Different hole types (longitudinal oblong, transversal oblong, elliptical, rectangular, diamond, longitudinal hexagonal, or transversal hexagonal) with different shapes (variation of characteristics dimensions of each hole type) are analyzed. Limit curves to avoid buckling were obtained, as well as the definition of the geometries that can improve up to 107% the plate performance.
RESUMO A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o d... more RESUMO A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o desenvolvimento de novos tipos de materiais, dentre os quais se destacam os materiais compósitos laminados reforçados por fibras. Placas finas construídas com estes materiais possuem diversas vantagens em comparação com as fabricadas com materiais de construção mecânica convencionais como o aço: altas relações rigidez/peso e resistência/peso; alta resistência à fadiga; e excelente resistência à corrosão. Portanto, a aplicação destes elementos estruturais é cada vez mais frequente em diversas áreas da engenharia, especialmente em estruturas navais e offshore. Neste contexto, o presente trabalho analisa numericamente o comportamento mecânico de placas finas fabricadas com diferentes tipos de materiais compósitos (Vidro-E / Epóxi, Boro / Epóxi, Tecido de Vidro / Epóxi e Boro / Alumínio) em comparação com o comportamento mecânico de uma placa de Aço. Os resultados mostraram que é possível obter com uma placa de material compósito reforçado por fibras um comportamento mecânico semelhante, ou até melhor, que o de uma placa de aço. PALAVRAS-CHAVES: Comportamento mecânico. Flexão de placas finas. Materiais compósitos. Simulação numérica.
Many steel structures such as ships and offshore structures are composed by welded stiffened or u... more Many steel structures such as ships and offshore structures are composed by welded stiffened or unstiffened plate elements. Cutouts are often provided in these plate elements for inspection, maintenance, and service purposes, and the size of these holes could be significant. In many situations, these plates are subjected to axial compressive forces which make them prone to instability or buckling. If the plate is slender, the buckling is elastic. However, if the plate is sturdy, it buckles in the plastic range causing the so-called inelastic (or elasto-plastic) buckling. Furthermore, the presence of these holes redistributes the membrane stresses in the plate and may cause significant reduction in its strength in addition to changing its buckling characteristics. So, the objective of this paper is to investigate the changes that the presence of circular holes produces in the elastic and inelastic buckling of steel rectangular plates. The finite element method (FEM) has been used to ...
RESUMO Placas finas de aco sao componentes muito utilizados em estruturas navais e oceânicas. Por... more RESUMO Placas finas de aco sao componentes muito utilizados em estruturas navais e oceânicas. Por se tratarem de elementos esbeltos, essas placas sao propensas a sofrerem o fenomeno da flambagem, quando submetidas a um carregamento de compressao axial. A realizacao de perfuracoes nestes componentes pode ser necessaria, o que gera uma redistribuicao de tensoes, causando mudancas no desempenho mecânico. Este trabalho propoe um estudo do fenomeno de flambagem em placas quadradas ou retangulares, simplesmente apoiadas e com perfuracao hexagonal longitudinal. A simulacao numerica foi utilizada para determinar a carga critica de flambagem e a carga de colapso da placa. O metodo Design Construtal foi aplicado, permitindo avaliar a influencia do grau de liberdade H 0 / L 0 (sendo H 0 a altura e L 0 o comprimento da perfuracao hexagonal), no comportamento mecânico das placas. A fracao de volume da perfuracao na placa ( ϕ ) tambem foi considerada, correspondendo a 10%, 15%, 20% e 25% do volum...
Placas finas de aco sao elementos estruturais de grande utilizacao nas mais diversas areas da eng... more Placas finas de aco sao elementos estruturais de grande utilizacao nas mais diversas areas da engenharia. Em algumas situacoes de projeto, as placas podem estar submetidas a esforcos de compressao, e como consequencia, podem estar sob o efeito da flambagem elastica e/ou elasto-plastica. Existem diferencas significativas na analise do fenomeno da flambagem entre elementos unidimensionais, como as vigas e as colunas, e em elementos bidimensionais, como as placas. O fenomeno da flambagem e dependente de aspectos dimensionais, construtivos e/ou operacionais. A inclusao de perfuracoes em placas provoca uma redistribuicao de suas tensoes, afetando nao apenas sua resistencia, mas tambem, suas caracteristicas de flambagem. Este artigo utilizou modelos computacionais desenvolvidos no ANSYS®, cuja base esta fundamentada no Metodo dos Elementos Finitos (MEF), para resolver o problema da flambagem elasto-plastica em placas finas perfuradas de aco. Foram consideradas para a analise placas com H/...
Revista de Engenharia Térmica
Buckling is an instability phenomenon that can happen in slender structural components when subje... more Buckling is an instability phenomenon that can happen in slender structural components when subjected to a compressive axial load. This phenomenon can occur due to an externally applied force, which when exceed a certain limit, called critical load, will promote the mechanical buckling on the structural member. Another buckling possibility happens to statically indeterminate structural elements when submitted to a positive temperature variation. As the axial displacements are restricted, if the temperature gradient is larger than the critical temperature variation, it will be generated a compressive axial load higher than the critical load of the structural component and the thermal buckling will occur. In this context, the present work presents a computational model to solve the thermal buckling problem of columns. A thin shell finite element, called SHELL93, was adopted for the computational domain discretization. It was employed a solution involving homogeneous algebraic equation...
A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o desenvol... more A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o desenvolvimento de novos tipos de materiais, dentre os quais se destacam os materiais compositos laminados reforcados por fibras. Placas finas construidas com estes materiais possuem diversas vantagens em comparacao com as fabricadas com materiais de construcao mecânica convencionais como o aco: altas relacoes rigidez/peso e resistencia/peso; alta resistencia a fadiga; e excelente resistencia a corrosao. Portanto, a aplicacao destes elementos estruturais e cada vez mais frequente em diversas areas da engenharia, especialmente em estruturas navais e offshore. Neste contexto, o presente trabalho analisa numericamente o comportamento mecânico de placas finas fabricadas com diferentes tipos de materiais compositos (Vidro-E / Epoxi, Boro / Epoxi, Tecido de Vidro / Epoxi e Boro / Aluminio) em comparacao com o comportamento mecânico de uma placa de Aco. Os resultados mostraram que e possivel obter com ...
Journal of Engineering Thermophysics
Perforated steel plates are structural components widely employed in engineering. In several appl... more Perforated steel plates are structural components widely employed in engineering. In several applications these panels are subjected to axial compressive load, being undesired the occurrence of buckling. The present work associates the computational modeling and the constructal design method to obtain geometries, which maximizes the mechanical behavior for these components. A numerical model was used to tackle with elastic and elasto-plastic buckling. Square and rectangular plates with centered elliptical cutouts were considered and several hole volume fractions and ratios between the ellipse axes (H0/L0) were taken into account. Stress limit improvements around 100% were achieved depending only on the cutout shape.
Research on Engineering Structures & Materials
Latin American Journal of Solids and Structures, 2016
Vetor Revista De Ciencias Exatas E Engenharias, Dec 27, 2013
Many steel structures such as ships and offshore structures are composed by welded stiffened or u... more Many steel structures such as ships and offshore structures are composed by welded stiffened or unstiffened plate elements. Cutouts are often provided in these plate elements for inspection, maintenance, and service purposes, and the size of these holes could be significant. In many situations, these plates are subjected to axial compressive forces which make them prone to instability or buckling. If the plate is slender, the buckling is elastic. However, if the plate is sturdy, it buckles in the plastic range causing the so-called inelastic (or elasto-plastic) buckling. Furthermore, the presence of these holes redistributes the membrane stresses in the plate and may cause significant reduction in its strength in addition to changing its buckling characteristics. So, the objective of this paper is to investigate the changes that the presence of circular holes produces in the elastic and inelastic buckling of steel rectangular plates. The finite element method (FEM) has been used to evaluate the elastic and elastoplastic buckling load of uniaxially loaded rectangular plates with circular cutouts. By varying the hole diameter, the plate aspect ratio and the plate thickness during the analyses, the changes in the plate buckling behavior can be determined. The results show that while the circular hole can in some cases even increase the elastic buckling load, the elasto-plastic buckling load is reduced by the presence of the cutout.
Proceedings of the XXXVI Iberian Latin American Congress on Computational Methods in Engineering, 2015
Many elements in engineering are formed by thin plates. Hulls and decks of ships are examples of ... more Many elements in engineering are formed by thin plates. Hulls and decks of ships are examples of application. These elements can have holes that serve as inspection port, access or even to weight reduction. The presence of holes causes a redistribution of the membrane stresses in the plate, significantly altering their stability. In this paper the Bejan’s Constructal Theory was employed to discover the best geometry of thin perforated plates submitted to elastic buckling phenomenon. To study this behavior simply supported rectangular plates with a centered elliptical perforation were analyzed. The purpose was to obtain the optimal geometry which maximizes the critical buckling load. For this, the degrees of freedom H/L (ratio between width and length of the plate) and H0/L0 (ratio between the characteristic dimensions of the hole) were varied. Moreover, different values of hole volume fraction ϕ (ratio between the perforation volume and the massive plate volume) were also investigat...
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2019
Slenderness is a remarkable geometrical characteristic of thin steel plates. When a slender plate... more Slenderness is a remarkable geometrical characteristic of thin steel plates. When a slender plate is subjected to an axial compression loading, a mechanical behavior called buckling can occur, causing an out-of-plane displacement. This instability phenomenon can be divided into elastic buckling (linear) and elasto-plastic buckling (nonlinear), depending on dimensional, constructive, or operational aspects. Moreover, in several practical situations, it is necessary to provide holes on thin steel plates, causing stress redistribution and changes in its buckling behavior. The present work purposes a buckling study in square and rectangular plates, simply supported, with two different centered perforations types: longitudinal hexagonal and transverse hexagonal. Numerical simulation, using the ANSYS ® software, was employed to determine the critical buckling load and the ultimate buckling load of the plates. The constructal design method was applied, allowing evaluating the variation effect of the degree of freedom H 0 /L 0 (being H 0 the width and L 0 the length of the perforation) on the plate's mechanical buckling behavior. The hole volume fraction (ϕ) was another considered parameter, corresponding to cutouts of 10%, 15%, 20%, and 25% of the total plate volume. The results showed the direct influence of the H 0 /L 0 ratio on the buckling type, allowing the definition of a buckling stress limit curve for each cutout type and hole volume fraction. Besides, the constructal design method, associated with the exhaustive search technique, enabled to define the optimized geometric configuration for each hole type that conducted the plate to a maximized mechanical performance.
Proceedings of the XXXVI Iberian Latin American Congress on Computational Methods in Engineering, 2015
Proceedings of the 23rd ABCM International Congress of Mechanical Engineering, 2015
Scientia Plena, 2019
As evoluções no desenvolvimento de materiais compósitos possibilitam cada vez mais o seu uso. Alg... more As evoluções no desenvolvimento de materiais compósitos possibilitam cada vez mais o seu uso. Algumas das ferramentas que contribuíram para essa evolução foram o Método dos Elementos Finitos e as ferramentas de simulação numérica, pois possibilitaram a avaliação do comportamento e da resistência desses materiais ainda na fase de projeto. Esses métodos permitem ao pesquisador conhecer de maneira muito próxima o comportamento dos elementos e das estruturas, porém, como são métodos aproximados, não se pode esperar que os resultados fossem exatamente iguais aos reais. Este trabalho procura analisar o comportamento mecânico de placas finas de materiais compósitos laminados reforçados por fibras submetidas a esforços de flexão, comparando-as com o de uma placa de aço. Para a modelagem computacional do problema utilizouse o software Abaqus 2017 Student Version® cuja base está fundamentada no Método dos Elementos Finitos. Na sequência, busca-se comparar os resultados obtidos neste trabalho ...
Steel plates are used in a great variety of engineering applications, such as deck and bottom of ... more Steel plates are used in a great variety of engineering applications, such as deck and bottom of ship structures, and platforms of offshore structures. Cutouts are often provided in plate elements for inspection, maintenance, and service purposes. So, the design of shape and size of these holes is significant. Usually these plates are subjected to axial compressive forces which make them prone to instability or buckling. If the plate is slender, the buckling is elastic. However, if the plate is sturdy, it buckles in the plastic range causing the so-called inelastic (or elasto-plastic) buckling.Therefore, the goal of this work is to obtain the optimal geometry which maximizes the buckling load for steel plates with a centered elliptical perforation when subjected to linear and nonlinear buckling phenomenon by means of Constructal Design. To do so, numerical models were developed in ANSYS software to evaluate the elastic and elasto-plastic buckling loads of simply supported and uniaxi...
Scientia Plena, 2015
Placas finas de aço são elementos estruturais muito utilizados em diversas aplicações de engenhar... more Placas finas de aço são elementos estruturais muito utilizados em diversas aplicações de engenharia, como em plataformas offshore, pontes, navios, aviões e automóveis. Porém, em algumas situações específicas as placas podem sofrer flambagem térmica, que é uma deflexão lateral causada simplesmente por um aumento de temperatura (variação crítica de temperatura). Este artigo utilizou um modelo computacional desenvolvido no software ANSYS, que é baseado no Método dos Elementos Finitos (MEF), para tratar o problema da flambagem térmica em placas. O modelo numérico foi verificado através da comparação de seus resultados com a solução analítica do problema. Foram analisadas placas com diferentes relações de…
Latin American Journal of Solids and Structures, 2016
Perforated steel thin plates are commonly used in structural engineering. Due to their geometric ... more Perforated steel thin plates are commonly used in structural engineering. Due to their geometric characteristics, these panels can suffer the undesired buckling phenomenon. In this context, the present work associates the computational modeling and the constructal design method to evaluate the influence of the geometric configuration in the plate buckling behavior, using the exhaustive search method to determine which geometries conduct to superior mechanical behavior. To do so, numerical models are employed to solve elastic and elasto-plastic buckling of plates having a centered perforation. Different hole types (longitudinal oblong, transversal oblong, elliptical, rectangular, diamond, longitudinal hexagonal, or transversal hexagonal) with different shapes (variation of characteristics dimensions of each hole type) are analyzed. Limit curves to avoid buckling were obtained, as well as the definition of the geometries that can improve up to 107% the plate performance.
RESUMO A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o d... more RESUMO A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o desenvolvimento de novos tipos de materiais, dentre os quais se destacam os materiais compósitos laminados reforçados por fibras. Placas finas construídas com estes materiais possuem diversas vantagens em comparação com as fabricadas com materiais de construção mecânica convencionais como o aço: altas relações rigidez/peso e resistência/peso; alta resistência à fadiga; e excelente resistência à corrosão. Portanto, a aplicação destes elementos estruturais é cada vez mais frequente em diversas áreas da engenharia, especialmente em estruturas navais e offshore. Neste contexto, o presente trabalho analisa numericamente o comportamento mecânico de placas finas fabricadas com diferentes tipos de materiais compósitos (Vidro-E / Epóxi, Boro / Epóxi, Tecido de Vidro / Epóxi e Boro / Alumínio) em comparação com o comportamento mecânico de uma placa de Aço. Os resultados mostraram que é possível obter com uma placa de material compósito reforçado por fibras um comportamento mecânico semelhante, ou até melhor, que o de uma placa de aço. PALAVRAS-CHAVES: Comportamento mecânico. Flexão de placas finas. Materiais compósitos. Simulação numérica.
Many steel structures such as ships and offshore structures are composed by welded stiffened or u... more Many steel structures such as ships and offshore structures are composed by welded stiffened or unstiffened plate elements. Cutouts are often provided in these plate elements for inspection, maintenance, and service purposes, and the size of these holes could be significant. In many situations, these plates are subjected to axial compressive forces which make them prone to instability or buckling. If the plate is slender, the buckling is elastic. However, if the plate is sturdy, it buckles in the plastic range causing the so-called inelastic (or elasto-plastic) buckling. Furthermore, the presence of these holes redistributes the membrane stresses in the plate and may cause significant reduction in its strength in addition to changing its buckling characteristics. So, the objective of this paper is to investigate the changes that the presence of circular holes produces in the elastic and inelastic buckling of steel rectangular plates. The finite element method (FEM) has been used to ...
RESUMO Placas finas de aco sao componentes muito utilizados em estruturas navais e oceânicas. Por... more RESUMO Placas finas de aco sao componentes muito utilizados em estruturas navais e oceânicas. Por se tratarem de elementos esbeltos, essas placas sao propensas a sofrerem o fenomeno da flambagem, quando submetidas a um carregamento de compressao axial. A realizacao de perfuracoes nestes componentes pode ser necessaria, o que gera uma redistribuicao de tensoes, causando mudancas no desempenho mecânico. Este trabalho propoe um estudo do fenomeno de flambagem em placas quadradas ou retangulares, simplesmente apoiadas e com perfuracao hexagonal longitudinal. A simulacao numerica foi utilizada para determinar a carga critica de flambagem e a carga de colapso da placa. O metodo Design Construtal foi aplicado, permitindo avaliar a influencia do grau de liberdade H 0 / L 0 (sendo H 0 a altura e L 0 o comprimento da perfuracao hexagonal), no comportamento mecânico das placas. A fracao de volume da perfuracao na placa ( ϕ ) tambem foi considerada, correspondendo a 10%, 15%, 20% e 25% do volum...
Placas finas de aco sao elementos estruturais de grande utilizacao nas mais diversas areas da eng... more Placas finas de aco sao elementos estruturais de grande utilizacao nas mais diversas areas da engenharia. Em algumas situacoes de projeto, as placas podem estar submetidas a esforcos de compressao, e como consequencia, podem estar sob o efeito da flambagem elastica e/ou elasto-plastica. Existem diferencas significativas na analise do fenomeno da flambagem entre elementos unidimensionais, como as vigas e as colunas, e em elementos bidimensionais, como as placas. O fenomeno da flambagem e dependente de aspectos dimensionais, construtivos e/ou operacionais. A inclusao de perfuracoes em placas provoca uma redistribuicao de suas tensoes, afetando nao apenas sua resistencia, mas tambem, suas caracteristicas de flambagem. Este artigo utilizou modelos computacionais desenvolvidos no ANSYS®, cuja base esta fundamentada no Metodo dos Elementos Finitos (MEF), para resolver o problema da flambagem elasto-plastica em placas finas perfuradas de aco. Foram consideradas para a analise placas com H/...
Revista de Engenharia Térmica
Buckling is an instability phenomenon that can happen in slender structural components when subje... more Buckling is an instability phenomenon that can happen in slender structural components when subjected to a compressive axial load. This phenomenon can occur due to an externally applied force, which when exceed a certain limit, called critical load, will promote the mechanical buckling on the structural member. Another buckling possibility happens to statically indeterminate structural elements when submitted to a positive temperature variation. As the axial displacements are restricted, if the temperature gradient is larger than the critical temperature variation, it will be generated a compressive axial load higher than the critical load of the structural component and the thermal buckling will occur. In this context, the present work presents a computational model to solve the thermal buckling problem of columns. A thin shell finite element, called SHELL93, was adopted for the computational domain discretization. It was employed a solution involving homogeneous algebraic equation...
A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o desenvol... more A crescente necessidade de estruturas com propriedades mecânicas superiores impulsiona o desenvolvimento de novos tipos de materiais, dentre os quais se destacam os materiais compositos laminados reforcados por fibras. Placas finas construidas com estes materiais possuem diversas vantagens em comparacao com as fabricadas com materiais de construcao mecânica convencionais como o aco: altas relacoes rigidez/peso e resistencia/peso; alta resistencia a fadiga; e excelente resistencia a corrosao. Portanto, a aplicacao destes elementos estruturais e cada vez mais frequente em diversas areas da engenharia, especialmente em estruturas navais e offshore. Neste contexto, o presente trabalho analisa numericamente o comportamento mecânico de placas finas fabricadas com diferentes tipos de materiais compositos (Vidro-E / Epoxi, Boro / Epoxi, Tecido de Vidro / Epoxi e Boro / Aluminio) em comparacao com o comportamento mecânico de uma placa de Aco. Os resultados mostraram que e possivel obter com ...
Journal of Engineering Thermophysics
Perforated steel plates are structural components widely employed in engineering. In several appl... more Perforated steel plates are structural components widely employed in engineering. In several applications these panels are subjected to axial compressive load, being undesired the occurrence of buckling. The present work associates the computational modeling and the constructal design method to obtain geometries, which maximizes the mechanical behavior for these components. A numerical model was used to tackle with elastic and elasto-plastic buckling. Square and rectangular plates with centered elliptical cutouts were considered and several hole volume fractions and ratios between the ellipse axes (H0/L0) were taken into account. Stress limit improvements around 100% were achieved depending only on the cutout shape.
Research on Engineering Structures & Materials
Latin American Journal of Solids and Structures, 2016
Vetor Revista De Ciencias Exatas E Engenharias, Dec 27, 2013
Many steel structures such as ships and offshore structures are composed by welded stiffened or u... more Many steel structures such as ships and offshore structures are composed by welded stiffened or unstiffened plate elements. Cutouts are often provided in these plate elements for inspection, maintenance, and service purposes, and the size of these holes could be significant. In many situations, these plates are subjected to axial compressive forces which make them prone to instability or buckling. If the plate is slender, the buckling is elastic. However, if the plate is sturdy, it buckles in the plastic range causing the so-called inelastic (or elasto-plastic) buckling. Furthermore, the presence of these holes redistributes the membrane stresses in the plate and may cause significant reduction in its strength in addition to changing its buckling characteristics. So, the objective of this paper is to investigate the changes that the presence of circular holes produces in the elastic and inelastic buckling of steel rectangular plates. The finite element method (FEM) has been used to evaluate the elastic and elastoplastic buckling load of uniaxially loaded rectangular plates with circular cutouts. By varying the hole diameter, the plate aspect ratio and the plate thickness during the analyses, the changes in the plate buckling behavior can be determined. The results show that while the circular hole can in some cases even increase the elastic buckling load, the elasto-plastic buckling load is reduced by the presence of the cutout.
Proceedings of the XXXVI Iberian Latin American Congress on Computational Methods in Engineering, 2015