Comportamento mecânico de materiais compósitos submetidos a impacto de baixa velocidade na presença de concentradores de tensão
Composites have been widely used in various engineering sectors due to specific high strength and high specific modulus. With the increasing application of composites, it is increasingly important to understand, predict and control their flaws in which defects can play a key role. Defects are imp...
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| Formato: | doctoralThesis |
| Idioma: | pt_BR |
| Publicado em: |
Universidade Federal do Rio Grande do Norte
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| Endereço do item: | https://repositorio.ufrn.br/handle/123456789/30750 |
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| Resumo: | Composites have been widely used in various engineering sectors due to
specific high strength and high specific modulus. With the increasing application of
composites, it is increasingly important to understand, predict and control their flaws in
which defects can play a key role. Defects are imperfections of materials generated in
manufacturing or during prolonged service. One of the most common defects in
composite processing refers to the formation of voids. Voids cause the reduction of
mechanical properties and therefore it is important to evaluate the behavior of the
material in the presence of this type of defect. Another factor that can lead to a
reduction in properties is the damage caused by low-speed impacts, generating
internal damage to the material compromising its integrity. This work aims to evaluate
the behavior due to the low velocity impact on polymeric composites considering stress
concentrators (two side holes at the point of impact) and find the residual mechanical
properties of these materials through fai (Flexural After Impact). In the analysis of
residual properties, the effects of damage and stress concentrators will be
dismembered by evaluating their individual influences on the increase of the stress
concentration factor (K). This dismemberment will be carried out through tests
considering the isolated effects of each case and a formulation that relates them. In
addition, it will also evaluate the influence of the percentage of voids on impact and
residual resistance by developing two composites based on fiberglass-E fabric with
different void percentages. From the tests performed, it was found that the damage
caused by the impact increased by 18% the concentration factor of the material, but in
the samples tested with lateral holes the damage had an influence of only 5% in the
reduction of the residual resistance |
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