The fiber pushout test is a mechanical test performed on composite materials where a fiber is mechanically pushed out of the material. This test is carried out with the purpose of measuring the matrix/fiber interface de-bonding energy and the effects of frictional sliding between the matrix and the fiber.
Load–displacement curve for fibre push-out test
Scanning electron microscope frame from an in-situ trench push-out experiment conducted on a Hi-Nicalon fibre[1]
To perform this test flat indentation tips, usually made of diamond or tungsten, are used. These tips are mechanically lowered onto the location of the fiber on the composite using a CCD
This test is not to be confused with fiber pull-out, which is a composite crack propagation phenomenon.
- The mechanics behind the test are as follows:
- 1. Elastic loading
- The flat tip indenter is lowered onto the fiber using a CCD camera to guide the indenter downwards
- 2. Progressive de-bonding
- The indenter touches the fiber and begins applying load, bonds begin to break between the matrix and the fiber
- 3. Fiber push through
- The bonds between the matrix and fiber are totally broken and the fiber begins to slide out of the matrix
- 4. Interfacial sliding
- the indenter continues to push the fiber through the matrix, the only force resisting this movement is frictional
- 5. Indenter matrix collision
- The fiber has been totally pushed out of the matrix and the indenter collides with the matrix surface. This gives the total displacement of the fiber.
References
edit- ^ De Meyere, Robin M. G.; Song, Kay; Gale, Louise; Harris, Stephen; Edmonds, Ian M.; Marrow, Thomas J.; Saiz, Eduardo; Giuliani, Finn; Armstrong, David E. J.; Gavaldà-Diaz, Oriol (2021-06-01). "A novel trench fibre push-out method to evaluate interfacial failure in long fibre composites". Journal of Materials Research. 36 (11): 2305–2314. doi:10.1557/s43578-021-00153-1. ISSN 2044-5326.
- Mechanical Behavior of Materials,(2009) Cambridge University Press by M.A. Meyers and K.K. Chawlars, Second Edition, Prentice-Hall, Upper Saddle River, NJ, 1999