Review: Fatigue of Fiber‑Reinforced Composites, Damage and Failure

Abstract

A concise review of fatigue of fber-reinforced composites,
covering fatigue life and damage development and how the properties of
constituents, orientations and other parameters affect fatigue life, is pre‑
sented. The subject broadly covers polymer, metal, and ceramic matrix
composites, by including specifc examples of fatigue data from litera‑
ture. Studies of composite fatigue have mostly evolved over the last 60
years, largely driven by aerospace applications of composites. The feld
is very vast in terms of accumulated technical literature and fatigue data.
Therefore, only some iconic examples, each with good experimen‑
tal data, have been considered in this review to illustrate the behavior
and the trends as clearly as possible. First, the general nature of tensile
deformation of fber composites under various combinations of fber and
matrix failure strains are reviewed to provide a background with which
the more complicated fatigue behavior can be easily understood. Sec‑
ond, examples of S–N fatigue data of glass (GFRP) and carbon (CFRP)
fber-reinforced plastics are provided, illustrating the effects of reinforce‑
ment, constituent properties, temperature, and orientation effects on
fatigue failure. These analyses are also modeled by S–N curve calcula‑
tions using exponential S–N fatigue constitutive equations proposed by
author. These calculations helped to easily rationalize the trends in S–N
data, as infuenced by strength and failure strains of fber and matrix.
Next, stiffness degradation behavior in fber composites are reviewed,
with specifc examples including CFRP (polymer matrix) and SiC/SiC
(ceramic matrix) composites. The nature of stiffness degradation is
also modeled using a semi-empirical equation that relates the fractional
remaining stiffness to fractional remaining fatigue life in the composite.
Finally, a few examples of fatigue behavior of laminated composites that
are typically used in real-world applications are reviewed