Fatigue Analysis and Test Procedures for the Design of Bonded Joints

The FAnTeStick project focuses on the experimental
evaluation of the fracture and fracture/fatigue behavior
of GFRP adhesively bonded joints. Two different
stacking sequences were evaluated.
The goal of the test campaigns was to characterize
the complete mixed-mode I+II fracture envelope
to use as a base for developing a predictive
numerical tool. For both layups, the quasi-static results
were similar; with a deviation of 10% for the
pure modes and less than 5% for mixed mode I+II.
The Benzeggagh-Kenane (B-K) fracture criterion was
used to describe the full mixed-modes I+II fracture
envelope. The B-K method relates the experimental
total energy release rate results as a function of the
mixed mode ratio. Such criteria proved to be highly
accurate to predict the mixed-mode fracture behavior.
In fact, for both series, a coefficient of determination
above 0.93 was obtained. Similarly, a numerical
model was employed to describe the quasi-static
fracture behavior by using the cohesive zone model
with a linear softening relation as the traction-separation
law. This modelling proved to be efficient in
describing the observed experimental behavior. For
loading modes with a predominance of mode I, the
numerical model proved to be even more reliable
and accurate.
In the case of the fatigue characterization, the goal
was to determine the fatigue life and a modified
Paris law representative of the fatigue fracture behavior
of both series. Fatigue tests were carried out
under pure tensile and shear loading. A power law
was fitted to the crack propagation experimental
data in order to obtain the best fit for the Paris law
shape parameters. For both stacking sequences

Field of competence

Industry sectors

Project status

  • Current




llona Kunzler

Scientific Staff Mechanical Charakterization & Modeling

Telephone: +49 631 2017 499


Francis González Ramírez

Scientific Staff Fatigue & Life Time Prediction

Telephone: +49 631 2017 157


The project “Fatigue Analysis and Test Procedures for the Design of Bonded Joints” is funded by the Federal Ministry for Economic Affairs and Climate Action on the basis of a decision of the German Bundestag (funding reference KK5003702EB0).