Sensitivity Analysis in a Fatigue Delamination Problem of an Elastic Two-Layer Composite

Several parameters can affect the fatigue delamination growth in laminates – these include
e.g. constituent material properties and/or composite shape. Knowledge about effects
of these parameters can lead to a better understanding of the fatigue delamination behaviour
and can also pinpoint directions for optimum composite design. These effects can be elucidated
by carrying out an appropriate sensitivity analysis. A FEM-based computational approach to
sensitivity analysis is proposed in this work to study composite parameter effects in a fatigue
delamination problem of an elastic two-layer composite. It is used to calculate and analyse sensitivity
gradients of the fracture parameter and fatigue cycle number with respect to composite
design parameters such as layer elastic constants. It is observed that sensitivities computed
from this approach are generally numerically stable. Obtained sensitivities pinpoint quantitatively
the most and least important composite parameters that govern a fatigue delamination
process. Sensitivity results are verified by another computational approach and a very good
agreement is found.