Análise numérica de perfis de aço formados a frio comprimidos considerando imperfeições geométricas iniciais
Data
2017-11-15
Autores
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Biblioteca Digital de Teses e Dissertações da USP
Universidade de São Paulo
Escola de Engenharia de São Carlos
Universidade de São Paulo
Escola de Engenharia de São Carlos
Resumo
Descrição
O presente trabalho apresenta proposta de análise numérica de perfis de aço formados a frio submetidos à compressão centrada. Trata-se de investigação, realizada por meio de elementos finitos, com vistas à análise da influência de imperfeições geométricas iniciais presentes em perfis U simples e U enrijecido, sob os aspectos de sua forma, magnitude e sentido. A imperfeição geométrica é adotada na forma de modos de falha local, global e distorcional, observando a suscetibilidade a tais modos para a seção de interesse. Cada tipo de imperfeição é avaliado de forma isolada e, em seguida, de forma associada (conjunta). São apresentados aspectos referentes à estratégia de modelagem adotada na construção dos modelos numéricos, bem como aspectos de interesse com relação às análises não-lineares aqui consideradas. Para fins de obtenção da força de colapso, fica examinada a possibilidade de empregar modos de falha isolados para representar as imperfeições geométricas, porém, com a amplitude previamente ajustada. Para os casos de imperfeições associadas, para representar a imperfeição geométrica, se destaca o papel do sentido da imperfeição do tipo global com relação a sua associação às imperfeições dos tipos local e distorcional para perfis U enrijecidos, bem como à imperfeição do tipo local para perfis U simples.
The work presents a numerical analysis on cold-formed steel members compressed between pinned ends. One is about an inquiry carried through in finite elements in which it was studied the influence of initial geometric imperfections, existing in plain channels and lipped channels, under the aspects of its form, magnitude and signal. The geometric imperfection is adopted on the forms of the local, global and distortional buckling modes, observing the susceptibility to such modes for each type of section. Each imperfection is evaluated on the isolated way and after that of associated way. Referring aspects to the strategy of modeling adopted in the construction of the numerical models are presented, as well as aspects of interest with regard to the developed nonlinear analyses. For ends of attainment of the ultimate load, it is examined the possibility to use isolated buckling modes to represent the geometric imperfections, as long as the amplitude it is adjusted. The cases that had applied coupled imperfection to represent the geometric imperfection detach the paper of the signal of the imperfection of the global type with regard to its association to the imperfections of the types local and distortional for lipped channels and, to the one of the local type for plain channels.
The work presents a numerical analysis on cold-formed steel members compressed between pinned ends. One is about an inquiry carried through in finite elements in which it was studied the influence of initial geometric imperfections, existing in plain channels and lipped channels, under the aspects of its form, magnitude and signal. The geometric imperfection is adopted on the forms of the local, global and distortional buckling modes, observing the susceptibility to such modes for each type of section. Each imperfection is evaluated on the isolated way and after that of associated way. Referring aspects to the strategy of modeling adopted in the construction of the numerical models are presented, as well as aspects of interest with regard to the developed nonlinear analyses. For ends of attainment of the ultimate load, it is examined the possibility to use isolated buckling modes to represent the geometric imperfections, as long as the amplitude it is adjusted. The cases that had applied coupled imperfection to represent the geometric imperfection detach the paper of the signal of the imperfection of the global type with regard to its association to the imperfections of the types local and distortional for lipped channels and, to the one of the local type for plain channels.
Palavras-chave
Análise numérica, Estruturas de aço, Imperfeições geométricas, Perfis formados a frio, Cold-formed members, Geometric imperfections, Numerical analysis, Steel structures