Publicação

Use of optical techniques in the assment of the displacement field near the crack tip

Ver documento

Detalhes bibliográficos
Resumo:A crack tip represents a highly singular stress field existing in a structural component. The evaluation of the associate strain gradient is difficult using experimental discrete methods. An efficient alternative relies on optical methods which are non contact and give continuous information about displacements fields and its derivatives for strain evaluation. This paper describes some experimental methods to fully characterize the displacement field near a crack tip existing in flat plates. Three optical field techniques based on image analysis were used in the present work; respectively ESPI (Electronic speckle pattern interferometry), MI (Moiré Interferometry), and DIC (digital image correlation). These methods present different resolutions which can be adjusted according to the expected strain gradient. While the first method depends on the laser wavelength, the second depends on the grid pitch and the last on the surface texture.
Autores principais:Ribeiro, J.E.
Outros Autores:Vaz, M.A.P.; Lopes, Hernani; Melo, F.J.M.Q. de; Monteiro, Jaime M.
Assunto:Optical Methods ESPI Moiré interferometry Digital image correlation Crack tip
Ano:2010
País:Portugal
Tipo de documento:documento de conferência
Tipo de acesso:acesso aberto
Instituição associada:Instituto Politécnico de Bragança
Idioma:inglês
Origem:Biblioteca Digital do IPB
Descrição
Resumo:A crack tip represents a highly singular stress field existing in a structural component. The evaluation of the associate strain gradient is difficult using experimental discrete methods. An efficient alternative relies on optical methods which are non contact and give continuous information about displacements fields and its derivatives for strain evaluation. This paper describes some experimental methods to fully characterize the displacement field near a crack tip existing in flat plates. Three optical field techniques based on image analysis were used in the present work; respectively ESPI (Electronic speckle pattern interferometry), MI (Moiré Interferometry), and DIC (digital image correlation). These methods present different resolutions which can be adjusted according to the expected strain gradient. While the first method depends on the laser wavelength, the second depends on the grid pitch and the last on the surface texture.