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Eklind, Alexander
Publications (3 of 3) Show all publications
Walander, T., Eklind, A., Carlberger, T., Stigh, U. & Rietz, A. (2016). Prediction of mixed-mode cohesive fatigue strength of adhesively bonded structure using Mode I data. International Journal of Adhesion and Adhesives, 66, 15-25
Open this publication in new window or tab >>Prediction of mixed-mode cohesive fatigue strength of adhesively bonded structure using Mode I data
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2016 (English)In: International Journal of Adhesion and Adhesives, ISSN 0143-7496, E-ISSN 1879-0127, Vol. 66, p. 15-25Article in journal (Refereed) Published
Abstract [en]

A cohesive zone model is presented for analyzing the fatigue life of an adhesive joint in the range of 104–106 load cycles. The parameters of the model are derived from Mode I double cantilever beam experiments. Fatigue experiments with adhesively joined components from the automotive industry are performed, and the results from the experiments are compared to the results of simulations. The error in the predicted fatigue strength is of the same order as the statistical deviation of the fatigue experiments, indicating that the simulation method produces acceptable predictions of the fatigue strength for applications in e.g. early product development.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Adhesive layer, Cohesive zone model, Damage, Fatigue, Finite element analysis
National Category
Vehicle Engineering
Research subject
Technology; Mechanics of Materials
Identifiers
urn:nbn:se:his:diva-11769 (URN)10.1016/j.ijadhadh.2015.12.003 (DOI)000371940600003 ()2-s2.0-84950250975 (Scopus ID)
Projects
ULFS: Fatigue of adhesively bonded structures
Funder
Knowledge Foundation, 20100214
Available from: 2015-12-18 Created: 2015-12-18 Last updated: 2019-01-22Bibliographically approved
Walander, T., Eklind, A., Carlberger, T. & Stigh, U. (2014). Fatigue damage of adhesive layers: experiments and models. Paper presented at 20th European Conference on Fracture (ECF20). Procedia Materials Science, 3, 829-834
Open this publication in new window or tab >>Fatigue damage of adhesive layers: experiments and models
2014 (English)In: Procedia Materials Science, ISSN 2211-8128, Vol. 3, p. 829-834Article in journal (Refereed) Published
Abstract [en]

Mode I fatigue crack growth at load levels close to the threshold is studied with the aim of improving the understanding of the fatigue properties. We also aim at identifying a suitable damage evolution law for large-scale simulation of built-up structures. A fatigue test rig is designed where up to six specimens are tested simultaneously. Each specimen is evaluated separately indicating the specimen-to-specimen variation in fatigue properties. A rubber-based and a PUR-based adhesive are tested. The two adhesives represent adhesives with very different material properties; the rubber adhesive is a stiff structural adhesive and the PUR adhesive is a soft modular adhesive. The experiments are first evaluated using a traditional Paris’ law approach. Inspired by an existing damage evolution law, a modified damage evolution law is developed based on only three parameters. The law is implemented as a user material in Abaqus and the parameters are identified. The results from simulations show a very good ability to reproduce the experimental data. With this model of fatigue damage, a zone of damage evolves at the crack tip. The extension of this zone depends on the stiffness of the adherends; stiffer adherends leads to a larger damage zone. This means that the rate of crack growth depends on the stiffness of the adherends. Thus, not only the state at the crack tip governs the rate of crack growth. This is in contrast to the results of a model based on Paris’ law where only the state at the crack tip, through the energy release rate, governs the rate of crack growth. This indicates that the threshold value of the energy release rate may depend on the stiffness of the adherends.

Place, publisher, year, edition, pages
Elsevier, 2014
National Category
Applied Mechanics
Research subject
Technology; Mechanics of Materials
Identifiers
urn:nbn:se:his:diva-9603 (URN)10.1016/j.mspro.2014.06.135 (DOI)000398274600130 ()
Conference
20th European Conference on Fracture (ECF20)
Projects
ULFS
Funder
Knowledge Foundation
Available from: 2014-06-27 Created: 2014-06-27 Last updated: 2019-03-04Bibliographically approved
Eklind, A., Walander, T., Carlberger, T. & Stigh, U. (2014). High cycle fatigue crack growth in Mode I of adhesive layers: modelling, simulation and experiments. International Journal of Fracture, 190(1-2), 125-146
Open this publication in new window or tab >>High cycle fatigue crack growth in Mode I of adhesive layers: modelling, simulation and experiments
2014 (English)In: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 190, no 1-2, p. 125-146Article in journal (Refereed) Published
Abstract [en]

The capability to predict high cycle fatigue properties of adhesive joints is important for cost-efficient and rapid product development in the modern automotive industry. Here, the adaptability of adhesives facilitates green technology through the widening of options of choosing and joining optimal materials. In the present paper a continuum damage mechanics model is developed based on the adhesive layer theory. In this theory, through-thickness averaged variables for the adhesive layer are used to characterise the deformation, damage and local loading on the adhesive layer. In FE-simulations, cohesive elements can thereby be used to model the adhesive layer. This simplifies simulations of large scale complex built-up structures. The model is adapted to experimental results for two very different adhesive systems; one relatively stiff rubber based adhesive and one soft polyurethane based adhesive. The model is able to reproduce the experimental results with good accuracy except for the early stage of crack propagation when the loads are relatively large. The model also predicts a threshold value for fatigue crack growth below which no crack growth occurs. The properties of the model are also compared with the properties of Paris’ law. The relations between the parameters of the continuum damage mechanics law and the parameters of Paris’ law are used to adapt the new law. It also shows that the properties of a joined structure influence the Paris’ law properties of the adhesive layer. Thus, the Paris’ law properties of an adhesive layer are not expected to be transferable to joints with adherends having different mechanical properties.

Place, publisher, year, edition, pages
Springer Netherlands, 2014
National Category
Applied Mechanics
Research subject
Technology; Mechanics of Materials
Identifiers
urn:nbn:se:his:diva-10219 (URN)10.1007/s10704-014-9979-8 (DOI)000345408700009 ()2-s2.0-84912026190 (Scopus ID)
Funder
Knowledge Foundation
Available from: 2014-11-25 Created: 2014-11-25 Last updated: 2019-01-22Bibliographically approved
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