Cadeia granular quase unidimensional como dispositivo para absorção de impactos

Detalhes bibliográficos
Ano de defesa: 2014
Autor(a) principal: Machado, Luis Paulo Silveira
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal da Paraí­ba
BR
Física
Programa de Pós-Graduação em Física
UFPB
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: https://repositorio.ufpb.br/jspui/handle/tede/5764
Resumo: Granular chains are one dimensional systems where elastic grains placed along a line are in contact and interact with neighbors. These systems are excellent nonlinear waveguides allowing the control of some properties of the wave through different disposition of the grains. Among the applications of practical interest, the impact absorption draws attention. In this thesis, we propose to study a tapered granular chain, very short and decorated with grains appropriately positioned to maximize shock absorption. We call this system quasi-one-dimensional chain, because it is a three-dimensional distribution of grains whose dynamic of interest take place along a fixed direction. To study the dynamics of this system, we integrated numerically the equations of motion. Perturbations caused by collision with the grains at the edge of the chain spread quickly throughout the system and do not propagate as solitary waves. Results shows that impact pulses are attenuated almost completely and combinations of materials are important. Futhermore, dissipation, gravity and impact velocities almost do not influence the dynamics of the system. The decorating grains act as an auxiliary chain which traps part of the energy and linear momentum, preventing the formation of pulses and playing a central role in impact mitigation. Therefore, we present a new granular chain where we increase the number of grains per units length and maximize the dispersion of the momentum.