PT  - JOURNAL ARTICLE
AU  - Zbončák, Radek
AU  - Votrubec, Vlastimil
AU  - Švec, Martin
TI  - The Alternative Procedures of Fiber Volume Ratio Determination of Long-Fiber Carbon - Epoxy Composites
DP  - 2018 Feb 1
TA  - Manufacturing Technology Journal
PG  - 160--164
VI  - 18
IP  - 1
AID - 10.21062/ujep/71.2018/a/1213-2489/MT/18/1/160
IS  - 12132489
AB  - The need to determine actual fiber volume ratio of the real composite part manufactured in the semi-closed mold led to application of the alternative procedures than the widely used Burn-off method. The low cost one, which is required preferably by any manufacturer, is based on Archimedes law (AL) and the most accurate determination of volume of displaced water. The more complex method which is based on the reverse engineering approach where the 3D scan technique is used to determine the volume of the part. Both are nondestructive methods. And finally the last method mentioned in this study is a sophisticated optical visualization technique and Figure post-processing by mathematical software (it was used NIS Elements and Wolfram Mathematica). Figures for mathematical post-processing were taken using light optical microscope (LOM) and scanning electron microscope (SEM). While better contrast between matrix and fibers is achieved in case of composites filled by transparent fibers, SEM figures provide better image contrast for non-transparent fibers.The AL and 3D measurement methods are very precise and suitable for orientative control during production, but they give only an average values of the fiber volume ratio in whole product. The mathematical post-processing of image is suitable for laboratory designing of composite part. It is destructive investigation method and image thresholding is time consuming, but on the other hand image processing gives the resultant fiber volume ratio in a particular cross section of the part. That makes the technique a good tool to find the weakest place of the part in meaning of the mechanical properties.