21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-4.4.4

SOME INVESTIGATIONS ON WOOD-COMPOSITE STRUCTURES FOR VERY LIGHT AIRCRAFT (VLA)

Jancelewicz B., Rodzewicz M., Czarnocki P., Salbut L.
Warsaw University of Technology, Poland

Keywords: wood-composite structures, very light aircraft (vla)

The results are presented of some investigations on selected properties of elements representing the wood composite structures useful for airframes of very light and ultra light aircraft. Wooden parts of the elements have been manufactured of the Polish pine and composite was glass-epoxy. Investigations on Young's modulus were performed with the use of four points bending beams for static values to be measured. Dynamic values of the modulus were measured using the one edge fixed beams free vibration frequency analysis. From this analysis the damping coefficient of free vibration amplitudes have been calculated. Dynamic values of Young's modulus of wood and composite as well pave been found as 10 -15% lower than the static ones. Damping coefficients versus frequency of free vibration of wood and wood-composite beams were found as non-linear. Investigation was also carried out on decreasing of strain concentration in wood -composite thin plate with knot in wood part. The fields of displacements and strains in elements tested have been found with the use of optical interference technique. Effective possibility of strains equalising was stated when using the one ply composite facing.

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