Daniel Helbig

STUDY ABOUT BUCKLING PHENOMENON IN PERFORATED THIN STEEL PLATES EMPLOYING COMPUTATIONAL MODELING AND CONSTRUCTAL DESIGN METHOD

PERFORATED STEEL THIN PLATES ARE COMMONLY USED IN STRUCTURAL ENGI-NEERING. 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.

Computational modeling and constructal design method applied to the mechanical behavior improvement of thin perforated steel plates subject to buckling

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.

SIMULAÇÃO NUMÉRICA E MÉTODO DESIGN CONSTRUTAL APLICADOS AO ESTUDO DE FLAMBAGEM EM PLACAS DE AÇO COM PERFURAÇÃO HEXAGONAL

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 volume total da placa. Os resultados mostraram a direta influencia da relacao H 0 /L 0 na ocorrencia da flambagem, para cada valor de fracao de volume estudada. Alem disso, o metodo Design Construtal, associado ao mecanismo de busca exaustiva, permitiu definir a geometrias otima para a perfuracao hexagonal nas placas. Palavras-chave: Placas de aco; Flambagem; Simulacao numerica; Design Construtal.