Effect of Environmental Gas Pressure on Measurement of Dynamic Bending Properties with Vibrating Reed Method

Abstract

Vibrating behaviours of different kinds of macromolecular materials under various environmental gas pressures were discussed with Nolle's model and the model proposed in the previous paper. The results are as follows : (1) From the vibrating behaviours in vacuum, it is known that fabrics under dynamic bending deformation cannot be commonly regarded as linear elastromer.(2) The effect of environmental gas pressures on nominal dynamic loss is great as contrasted with that on nominal dynamic modulus.(3) As dynamic displacement increases, the dynamic modulus of rubber sheet will increase while that of fabric will decrease.(4) The relative viscosity of fabric is greater than that of film made of the same material.(5) Well linear relationship is obtained between the change of reduced mass and the reciprocal of sample's thickness.(6) The relative air damping factor also varies propotionally to the reciprocal of sample's thickness.(7) Plot of the change of reduced mass against environmental gas pressure fits in with a straight line.(8) The relative air damping factor varies approximately in propotion to the two-thirds power of environmental gas pressure.