Investigations of Hollow Glass Fibers for the Development of Reinforced Plastics.

Results of attempts to make a hollow fiber for reinforcement purposes are reported. An optimal wall-thickness/diameter ratio was determined theoretically according to the elasticity of the resin matrix. Fiber diameter, wall-thickness, dimensional inhomogeneities and surface conditions as voids and cracks were subject of experimental investigations. The ultimate fiber strength was found to be rather low compared with the strength of solid fibers.