Exploring Preferential Energy Absorption in Fiber Aggregates at Low Frequencies, 1995 Pulping Conference Proceedings

C. B. Rueckert Ph. D. & A. W. Rudie

Institute of Paper Science and Technology

Previous research has shown that the earlywood portion of the annual growth ring appears to receive the majority of the energy in the early stages of chip refining. This study is attempting to determine if preferential energy absorption extends further into the refining process. Studies are being carried out on fiber aggregates, simulating a fiber floc in the coarse bars of a refiner. The fiber aggregates are cyclically compressed at 10 hertz on an MTS servo-hydraulic machine. Curl index, measured after various predetermined compression cycles, is used as an index of strain (an indirect measurement of energy applied to the fibers). The change in the curl indices of the earlywood and latewood fibers are then compared to determine if there is preferential energy absorption due to fiber type. Results of this study suggest there is a preferential energy absorption by the earlywood in the fiber aggregates compressed at low frequencies.