Ｆ．Ｒ．Ｐ．Ｅ．の繊維補強効果と溶接部の挙動

Abstract

This article seeks for an effect of glass fiber reinforcement in the construction of glass fiber reinforcement material. Furthermore, ultrasonic welding of F.R.P.E by batch method has been experimented, and behavior of weld under load is sought for. When the fibers are dispersed uniformly in matrix and basic unidirectional composite material is subjected to tension in the direction of fibers, law of mixture holds true on the assumption that fibers and matrix do not slip each other but receive the same strain.Same stress is transmitted to matrix as transmitted to fiber. But, since the fiber has extremely high modulus compared with matrix, elongation of matrix is much greater than that of fiber under the same tensile force. In consequence, difference in elongation of fiber and of matrix and shearing strain are considered to be accumulated and become greater and greater toward the ends of fibers. This condition is ascertained in the form of stress distribution by means of photo-elastic experiment based upon photo-elastic effect of matrix. Furthermore, the relationship among fiber length, clearance between fibers, lap length of fiber, and reinforcement effect of glass fiber is sought for by mechaincal test, as well as in correlation with photo-Blast:c experiment. Behavior of weld of F.R.P.E is examined on the other hand by mechaincal test and photo-elastic experiment.Tension test was carried out with universal testing machine with electronic tube, Autograph IM-100, and tenisle stress-strain and change in shape until failure have been observed. On the other hand, Autograph IS-2000 was combined with photo-elastic experiment device for photo-elastic experiment, with which interference fringe of double-refracted light under different loads has been photographed and dynamic distribution of internal strain has been obtaiaed. Material used for the experiment was polyethylene of low density and E-glass formed into F.R.P.E by hot press. Welding was carried out by ultrasonic welding method using Sonopet 1000 B.Relationship of L and Ts can be given in straight line, and so is relationship of Cc and Ts so long as Gc is less, than 30%. Relationship of C and Ts is on the other hand something like what is expressed by a curve of second degree, and C is desired to be as small as possible. No fiber reinforcement effect is expected unless Land Care with ineffective range. Failure in the course of tension occurs first at the tip of fiber and propagates to the side of tip. Tranasmission of stress by the effect of fiber reinforcement can be observed in photo-elastic phenomenon. In order to judge whether the welding is good or not, ratio of weld thickness serves as an effectual criterion. Welding joint efficiency of F.R.P.E was approximately 100%.