Temperature and Moisture Effects in a Particulate Interlayered Composite: Mode I Data Reduction and Toughness

Abstract

A study was conducted to determine the mode I toughness of T800H/3900-2 graphite/ epoxy under a range of environments that are typical of aircraft and spacecraft operating conditions. Double cantilever beam tests were performed on both dry and moisture-saturated specimens at temperatures of À43, 21, and 988C, and on dry specimens only at 1258C. Under certain conditions, nonlinear behavior and permanent deformations were observed. Thus, a sub-study was performed to choose a data reduction method that could be used to accurately obtain the mode I toughness under all test conditions, from which a 'load based compliance calibration method' was selected. At a given moisture content, it was found that toughness increased with increasing temperature. Except for precracked specimens at À438C, toughness was also found to increase with increasing moisture content. However, dramatically different behaviors were evidenced by the resistance curves from the various conditions. Aided by scanning electron microscopy, these results are explained by the mechanisms associated with crack advance, including the amount of plasticization of the matrix, matrix viscoelasticity, and the path of the growing delamination.

Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part II: Numerical Analysis

“…In the international literature, plenty of analytical research devoted to Mode I investigation can be found. Multiple data reduction methods based on Linear Elastic Fracture Mechanics (LEFM) have been developed and can be categorized as: the compliance calibration methods based on experiments defining the relationship of the compliance versus the crack length [28,29]; the compliance calibration methods derived from the classical and modified beam theory [30,31]; an approach determining the energy release rate from the ratio of change in strain energy to the change in crack area [32]; and a reduction method using the J-integral as a fracture parameter [33]. The expressions for critical energy release rate used in this work are based on the work of Williams [30,34] and Hashemi et al [31] leading to Equation (12).…”

Analysis of the Numerical and Geometrical Parameters Influencing the Simulation of Mode I and Mode II Delamination Growth in Unidirectional and Textile Composites

“…A lot of research has been effectuated on the analytical calculation of the mode I fracture toughness G Ic . Multiple data reduction methods based on Linear Elastic Fracture Mechanics (LEFM) have been developed and can be categorized as: the compliance calibration methods based on experiments defining the relationship of the compliance versus the crack length [28,29,30]; the compliance calibration methods derived from the classical and modified beam theory [31,32,33]; an approach determining the energy release rate from the ratio of change in strain energy to the change in crack area [33,34] and finally a reduction method using the Jintegral as a fracture parameter [3,35]. The expressions for G Ic used in this work are based on the work of Williams [31,36] and Hashemi et al [33] leading to the equations below.…”

Investigating the contribution of geometrical parameters and immersion time on fracture toughness of jute fabric composites using statistical techniques

“…Correspondingly needs to be characterizing the fracture toughness over environmental conditions. This behaviour has been interrelated to the effect of moisture on matrix ductility, an amount of matrix deformation and the size of the plastic zone around the crack tip that occurs during fracture [4]. For fiber-reinforced composite materials, the interlaminar and/or intralaminar interface will have a great effect on their fracture mechanisms.…”