TY - JOUR

T1 - Effects of non-proportionality and tension–compression asymmetry on the fatigue life prediction of equivalent stress criteria

AU - Kuhn, Michael

AU - Manousides, Nikolas

AU - Antoniou, Alexandros

AU - Balzani, Claudio

N1 - Funding Information: This work was supported by the German Federal Ministry for Economic Affairs and Climate Action (BMWK) in the ReliaBlade project (Grants 0324335A and 0324335B). The authors would like to acknowledge the work of Martina Karalus and Henning Schnellen, who accompanied the fatigue experiments as technicians and implemented the machine code. Open Access funding enabled and organized by Projekt DEAL.

PY - 2023/8/10

Y1 - 2023/8/10

N2 - Biaxial tension/compression–torsion fatigue tests with varying levels of non-proportionality were performed employing a structural adhesive designed for wind turbine rotor blades. The cycles to failure were found to be independent of the level of non-proportionality. It is demonstrated that numerical fatigue life predictions via rainflow-counted equivalent stress histories are not able to replicate these experimental observations and overestimate the fatigue life up to a hundredfold. The tension–compression asymmetry of the adhesive resulted in significant damage prediction differences depending on the stress space representation of the Haigh diagram. If not properly taken care of, the asymmetry will also lead to non-conservative results. While demonstrated with a short fiber-reinforced adhesive, the results can be transferred to other materials.

AB - Biaxial tension/compression–torsion fatigue tests with varying levels of non-proportionality were performed employing a structural adhesive designed for wind turbine rotor blades. The cycles to failure were found to be independent of the level of non-proportionality. It is demonstrated that numerical fatigue life predictions via rainflow-counted equivalent stress histories are not able to replicate these experimental observations and overestimate the fatigue life up to a hundredfold. The tension–compression asymmetry of the adhesive resulted in significant damage prediction differences depending on the stress space representation of the Haigh diagram. If not properly taken care of, the asymmetry will also lead to non-conservative results. While demonstrated with a short fiber-reinforced adhesive, the results can be transferred to other materials.

KW - multiaxial fatigue

KW - non-proportionality

KW - structural adhesives

KW - tension–compression asymmetry

KW - wind turbine rotor blades

UR - http://www.scopus.com/inward/record.url?scp=85161400546&partnerID=8YFLogxK

U2 - 10.1111/ffe.14065

DO - 10.1111/ffe.14065

M3 - Article

AN - SCOPUS:85161400546

VL - 46

SP - 3161

EP - 3178

JO - Fatigue and Fracture of Engineering Materials and Structures

JF - Fatigue and Fracture of Engineering Materials and Structures

SN - 8756-758X

IS - 9

ER -