Fracture Strength Distribution in E-Glass Fiber Using Acoustic Emission

Abstract

The strength of unidirectional composites is essentially dependent on the mechanical behavior of their reinforcement. The variability in mechanical properties of glass fibers has been studied using bundles of about 1400 filaments. This article proposes an experimental study on the fiber fracture strength distributions during tensile test by using acoustic emission (AE) in order to verify individual filament failures. AE monitoring of a bundle of E-glass fibers provides a convenient and relatively quick method to obtain the Weibull parameters of strength distribution. Results show that AE can be used as an effective tool to recognize the failure strength distribution as well as flaw population of fibers.

Study of the pull-out test of multifilament yarns embedded in cementitious matrix

“…The following decrease corresponds to the successive failures of the remaining unbroken filaments. 41 The hypothesis of a chemical degradation of the sizing or of the glass filaments in water can be refuted since the third test shows a mechanical behaviour similar to the one of yarn taken from the spool for yarn after 28 days of immersion in water with edges constrained (preventing the geometrical reorganization of the filaments).…”

Amplitude-Energy Parameters of Acoustic Radiation with Composite Properties Changing and Mieses Destruction

“…However, in most of the articles, the process of CM destruction under tension conditions is considered. At the same time, using the general provisions of the FBM concept for the analysis of CM destruction processes, additional conditions are introduced: the introduction of two subsets of fibers, one of which is characterized by a probabilistic distribution tensile strength [18]; each fiber having thermal fluctuations of its energy characteristics in the form of white Gaussian noise, which add to the fiber fracture stresses [19]; varying dimension of the system from location fibers at an equal distance from each other along the line to location the fibers at the nodes a square lattice with side L [20]; restoration (sintering) of broken fibers and relaxation of load inhomogeneities (sintering compensates for damage by creating additional undamaged load-bearing fibers, which leads to increase the strength of bundle) [14]; the randomness of fiber configuration, that is, random distribution of fibers along the length [21]; strength distribution of elements according to Weibull [22]; the use of different distributions of threshold levels of destruction [23]; modeling of two materials with different mechanical properties that interact with each other [24]; and others. When modifying models, as a rule, studies are carried out on stresses change, the number of destroyed or remaining elements, time of composite full destruction change, distributions of destruction avalanches change (the number of fiber failures that occur due to the destruction of one fiber) and other characteristics.…”

Studying acoustic emission by fitting the destruction models of a composite according to the or criterion and Mises criterion

“…The advancement of these studies is considered in paper [6]. The basic provisions of the FBM model are considered in [7], with the assumption about the distribution of the strength of CM elements according to Weibull, as evidenced by experimental studies involving AE. It shows that AE allows rapid determination of the distribution parameters according to Weibull.…”