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Abstract(s)
Os danos provocados pelo impacto de baixa velocidade constituem um desafio no campo dos materiais compĂłsitos. Contrariamente aos metais, o dano em compĂłsitos inicia-se geralmente no seu interior sob a forma de fissuras na matriz, delaminaçÔes e rotura de fibras. Tais danos apresentam um efeito bastante acentuado na resistĂȘncia mecĂąnica, por esse motivo diversos estudos tĂȘm sido desenvolvidos no sentido de se caraterizar o comportamento ao impacto de estruturas compĂłsitas.
Esta dissertação tem, assim, o objetivo de avaliar a resistĂȘncia ao impacto de baixa velocidade em placas curvas com diferentes espessuras. Este tĂłpico revela-se de extrema importĂąncia, uma vez que os compĂłsitos permitem o fabrico de peças Ășnicas com configuraçÔes complexas. Neste caso particular, para placas com geometrias curvas, verificou-se que o aumento da espessura resulta num aumento da rigidez da placa, a qual apresenta uma influĂȘncia significativa no comportamento ao impacto. Assim, maiores espessuras conduzem a maiores cargas de impacto, menores deflexĂ”es e tempos de contato bem como danos induzidos. Consequentemente, uma maior espessura conduz a uma maior vida de fadiga.
The damages caused by low velocity impact are a great challenge on the composite materials field. Contrary to metals, the damage in composites generally starts inside as cracks in the matrix, delamination and fiber breakage. Such damages can have a great effect on the mechanical strength, therefore several studies have been developed to characterize the impact behavior of composite structures. This dissertation thus has the objective of evaluation the resistance to the low speed impact on curved plates with different thicknesses. This topic proves to be of utmost importance since composites allow the manufacture of single parts with complex geometries. In this case, for plates with curved geometries it has been found that increasing the thickness results in an increase in the rigidity of the plate, which has a significant influence on the impact behavior. Thus, greater thicknesses lead to higher impact loads and lower deflections, contact times and damage severities. Consequently, a greater thickness leads to a longer life of fatigue.
The damages caused by low velocity impact are a great challenge on the composite materials field. Contrary to metals, the damage in composites generally starts inside as cracks in the matrix, delamination and fiber breakage. Such damages can have a great effect on the mechanical strength, therefore several studies have been developed to characterize the impact behavior of composite structures. This dissertation thus has the objective of evaluation the resistance to the low speed impact on curved plates with different thicknesses. This topic proves to be of utmost importance since composites allow the manufacture of single parts with complex geometries. In this case, for plates with curved geometries it has been found that increasing the thickness results in an increase in the rigidity of the plate, which has a significant influence on the impact behavior. Thus, greater thicknesses lead to higher impact loads and lower deflections, contact times and damage severities. Consequently, a greater thickness leads to a longer life of fatigue.
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Keywords
Fibra de Vidro Placas Curvas ResistĂȘncia Ao Impacto