On the Stress-Strain Curve of Polyethylene Filled with Randomly Oriented Glass Fibers

Abstract

In this paper is presented a report of the studies made of the specimens which were made up of polyethylene resin filled with randomly oriented short glass fibers, the effect of the fibers of finitely short length and embedded in the random orientation on the stress-strain curve of FRTP, and the S-s curve which was analyzed by using the law of mixture. As the result the following conclusions have been obtained.
(1) The stress-strain curve of FRTP is separable into two parts, i. e., the part A, which gives rise to the elastic deformation of the glass, and the other the part B, in which alone the plastic deformation of the specimen takes place.
(2) The strain ε separating the part A from the part B, can be theoretically evaluated from Eq.(10) in this paper.
(3) The convert of the part A to the part B does not discontinuously occur at the strain ε, but continuously appears in the vicinity of ε.
(4) The strain ε signifies onset of the fracture process with FRP with little ductility in contrast.
(5) As compared with the glass volume fraction, the bearing load fraction of the total glass embedded in FRTP is very small. The reason for this is that there are two facts that the glass fiber is very short and that it is embedded in a state of random orientation.