一方向ＣＦＲＰおよびＧＦＲＰのねじり挙動

Abstract

The helicopter bearingless rotor flexbeam is usually made of glass-fiber reinforced plastic composite (GFRP). For improving performance and reliability as well as the reduction of maintenance cost and weight, CFRP is expected to be applied to the flexbeam of the rotor system in future. However, few researches regarding torsion behavior of unidirectional CFRP have been made. In this study, torsion behavior of unidirectional CFRP and GFRP was examined in detail. A two-axis tension/ torsion examination device was used to observe torsion behavior of CFRP and GFRP. It was confirmed that the behavior of such materials is comprised of linearity/non-linearity domains. In addition, off-axis tension tests were performed in order to explain a non-linear behavior with a one-parameter plasticity model proposed by Sun et al., and a plasticity parameter for each of the materials was obtained. A prediction of a linear/non-linear behavior also became possible by incorporating the 3-D plasticity model into an FEM analysis with the estimated plastic parameters. The torsional rigidities of CFRP and GFRP are almost the same. This suggests that GFRP can be replaced by CFRP as torsional elements of a helicopter flex beam without an increase in torsion torque of the rotor system.