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An electrical method of measuring crack length during crack propagation tests of polymers
Author(s) -
Serrano A. M.,
Welsgh G. E.,
Gibala R.
Publication year - 1982
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760221505
Subject(s) - materials science , electrical conductor , composite material , tension (geology) , surface tension , electrically conductive , crack closure , grid method multiplication , fracture mechanics , microscope , grid , polymer , deformation (meteorology) , optics , geometry , ultimate tensile strength , physics , mathematics , quantum mechanics
Measurement of fatigue crack propagation rate ( da/dn ) in polymers is normally done optically with a travelling microscope. Electrical methods have not been very successful due to lack of sensitivity and to inaccuracies caused by factors such as plastic deformation and temperature variation. Use of electrically conductive surface grids eliminates these problems. An electrically conductive grid pattern is vapor‐deposited onto the surface of a compact tension specimen. The electrically conductive grid pattern is vapor‐deposited onto the surface of a compact tension specimen. The electrically conductive grid lines run across the expected path of the crack. With crack advancement, the grid lines are successively torn apart. Proper interpretation of the discontinuous steps that result when electrical current is plotted against time directly generates da / dn data.