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Papers by Adriana Diacenco
O presente trabalho propõe-se a analisar a influência do amortecimento estrutural inerente de tai... more O presente trabalho propõe-se a analisar a influência do amortecimento estrutural inerente de tais materiais submetidos a perturbações estáticas e dinâmicas as quais afetam as características de resposta. A importância deste trabalho insere-se no contexto do controle de vibrações de sistemas de engenharia. Para tanto, é empregada uma técnica de modelagem baseada em elementos finitos. A análise numérica é desenvolvida utilizando a Teoria da Deformação Cisalhante, a qual é implementada em um elemento Serendipity retangular contendo oito nós. O amortecimento é incluído empregando o modelo histerético. As respostas dinâmicas são representadas por funções de resposta em freqüência e autovalores complexos. Simulações numéricas são realizadas visando quantificar os níveis de amortecimento obtidos no tocante às vibrações transversais de placas retangulares e verificar a possibilidade de se aumentar tal amortecimento. Palavras-chave: Amortecimento inerente; Material compósito; Elementos finitos; FSDT.
Composite materials have been regarded as a convenient strategy in various types of engineering s... more Composite materials have been regarded as a convenient strategy in various types of engineering systems such as aeronautical and space structures, as well as architecture and light industry products. It is due to its advantages to the traditional engineering materials, characterized by its low density associated with high strength/stiffness relation characteristics, and its anti-corrosion properties. However, the great variety of materials properties and structural configurations makes the numerical modeling of the mechanical behavior of composite structures a complex task. Moreover, applications to the case of vibration and damping analysis of composite sandwich plates incorporating viscoelastic materials are not numerous, which motivates the study reported herein. This is a reason for which in the last decades, a great deal of effort has been devoted to the development of finite element models for characterizing the mechanical behavior of composite sandwich plates with viscoelastic layers, accounting for its typical variations of constructions, various orientations possibilites and the damping effects. In this paper the finite element modeling of composite sandwich plates incorporating viscoelastic materials is presented. The incorporation of the viscoelastic behavior into the composite sandwich finite element models is made by using the complex modulus approach and the numerical resolution of the resulting equations of motion are particularly relevant aspects of the modeling procedures since the viscoelastic stiffness matrix is frequency-and temperature-dependent. After the discussion of various theoretical aspects, the frequency responses functions are calculated for a rectangular composite sandwich plate with viscoelastic layers. Moreover, in this paper the formulation of first-order sensitivity analysis of complex frequency response functions is developed for composite sandwich plates with viscoelastic damping. The results obtained are compared with the corresponding obtained for a composite plate without damping, and the usefulness of the sensitivity modeling methodology in various types of analyses and design of composite sandwich plates incorporating viscoelastic damping is highlighted.
O presente trabalho propõe-se a analisar a influência do amortecimento estrutural inerente de tai... more O presente trabalho propõe-se a analisar a influência do amortecimento estrutural inerente de tais materiais submetidos a perturbações estáticas e dinâmicas as quais afetam as características de resposta. A importância deste trabalho insere-se no contexto do controle de vibrações de sistemas de engenharia. Para tanto, é empregada uma técnica de modelagem baseada em elementos finitos. A análise numérica é desenvolvida utilizando a Teoria da Deformação Cisalhante, a qual é implementada em um elemento Serendipity retangular contendo oito nós. O amortecimento é incluído empregando o modelo histerético. As respostas dinâmicas são representadas por funções de resposta em freqüência e autovalores complexos. Simulações numéricas são realizadas visando quantificar os níveis de amortecimento obtidos no tocante às vibrações transversais de placas retangulares e verificar a possibilidade de se aumentar tal amortecimento. Palavras-chave: Amortecimento inerente; Material compósito; Elementos finitos; FSDT.
Composite materials have been regarded as a convenient strategy in various types of engineering s... more Composite materials have been regarded as a convenient strategy in various types of engineering systems such as aeronautical and space structures, as well as architecture and light industry products. It is due to its advantages to the traditional engineering materials, characterized by its low density associated with high strength/stiffness relation characteristics, and its anti-corrosion properties. However, the great variety of materials properties and structural configurations makes the numerical modeling of the mechanical behavior of composite structures a complex task. Moreover, applications to the case of vibration and damping analysis of composite sandwich plates incorporating viscoelastic materials are not numerous, which motivates the study reported herein. This is a reason for which in the last decades, a great deal of effort has been devoted to the development of finite element models for characterizing the mechanical behavior of composite sandwich plates with viscoelastic layers, accounting for its typical variations of constructions, various orientations possibilites and the damping effects. In this paper the finite element modeling of composite sandwich plates incorporating viscoelastic materials is presented. The incorporation of the viscoelastic behavior into the composite sandwich finite element models is made by using the complex modulus approach and the numerical resolution of the resulting equations of motion are particularly relevant aspects of the modeling procedures since the viscoelastic stiffness matrix is frequency-and temperature-dependent. After the discussion of various theoretical aspects, the frequency responses functions are calculated for a rectangular composite sandwich plate with viscoelastic layers. Moreover, in this paper the formulation of first-order sensitivity analysis of complex frequency response functions is developed for composite sandwich plates with viscoelastic damping. The results obtained are compared with the corresponding obtained for a composite plate without damping, and the usefulness of the sensitivity modeling methodology in various types of analyses and design of composite sandwich plates incorporating viscoelastic damping is highlighted.