Premium
The analysis of fibre distributions in fibre reinforced materials *
Author(s) -
Stroeven Piet
Publication year - 1977
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1977.tb00069.x
Subject(s) - orientation (vector space) , planar , projection (relational algebra) , fracture (geology) , materials science , plane (geometry) , degree (music) , computer science , feature (linguistics) , basis (linear algebra) , biological system , composite material , algorithm , mathematics , geometry , acoustics , physics , linguistics , philosophy , computer graphics (images) , biology
SUMMARY Different spacing factors and various orientation efficiency factors, applied to characterize the spatial distribution of the (steel) fibres in fibre reinforced cementitious materials, cannot constitute a sound basis for a mutual comparison of experiments or for an evaluation of experiments in a fracture mechanical sense. This paper therefore presents a complete framework, based on geometrical probability theory, providing the investigator with methods to obtain three‐dimensional information from two‐dimensional images produced by X‐ray radiography. In this approach the fibres are assumed to be disposed in such a way that on the average a partially planar‐oriented structure is obtained. In addition, because of their high aspect ratio, the fibres are considered to be lineal features. Two methods are elaborated, i.e. the feature counting technique and the method of directed secants. These operations have to be performed in the projection plane. Both methods yield data on the degree of inhomogeneity (segregation) and the degree of orientation (anisometry), as well as on spacing and orientation efficiency. By substituting design data in the presented formulae, this framework can also serve to characterize the spatial properties of the fibre structure in the designed mix. The application of the theory is illustrated with the help of data that confirm the occurrence of segregation and preferred orientation effects due to vibration of the specimens.