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Gåård, Anders
Alternative names
Publications (10 of 49) Show all publications
AlMotasem, A. T., Bergström, J., Gåård, A., Krakhmalev, P. & Holleboom, T. J. (2017). Atomistic insights on the wear/friction behavior of nanocrystalline ferrite during nanoscratching as revealed by molecular dynamics. Tribology letters, 65(3), 101
Open this publication in new window or tab >>Atomistic insights on the wear/friction behavior of nanocrystalline ferrite during nanoscratching as revealed by molecular dynamics
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2017 (English)In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 65, no 3, p. 101-Article in journal (Refereed) Published
Abstract [en]

Using embedded atom method potential, extensive large-scale molecular dynamics (MD) simulations of nanoindentation/nanoscratching of nanocrystalline (nc) iron have been carried out to explore grain size dependence of wear response. MD results show no clear dependence of the frictional and normal forces on the grain size, and the single-crystal (sc) iron has higher frictional and normal force compared to nc-samples. For all samples, the dislocation- mediated mechanism is the primary cause of plastic deformation in both nanoindentation/nanoscratch. However, secondary cooperative mechanisms are varied significantly according to grain size. Pileup formation was observed in the front of and sideways of the tool, and they exhibit strong dependence on grain orientation rather than grain size. Tip size has significant impact on nanoscratch characteristics; both frictional and normal forces monotonically increase as tip radii increase, while the friction coefficient value drops by about 38%. Additionally, the increase in scratch depth leads to an increase in frictional and normal forces as well as friction coefficient. To elucidate the relevance of indentation/scratch results with mechanical properties, uniaxial tensile test was performed for nc-samples, and the result indicates the existence of both the regular and inverse Hall-Petch relations at critical grain size of 110.9 angstrom. The present results suggest that indentation/scratch hardness has no apparent correlation with the mechanical properties of the substrate, whereas the plastic deformation has.

Place, publisher, year, edition, pages
New York: Springer, 2017
National Category
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-63698 (URN)10.1007/s11249-017-0876-y (DOI)000405488400027 ()
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-10-21Bibliographically approved
Gåård, A. (2017). Damage mechanisms for tools used in applications subjected to combined impact and wear. In: : . Paper presented at Euromat European congress and exhibition on advanced materials and processes 17-22 sept, Thessaloniki Greece.
Open this publication in new window or tab >>Damage mechanisms for tools used in applications subjected to combined impact and wear
2017 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kau:diva-63711 (URN)
Conference
Euromat European congress and exhibition on advanced materials and processes 17-22 sept, Thessaloniki Greece
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-05-20Bibliographically approved
Gåård, A. (2017). Damage mechanisms for tools used in applications subjected to combined wear and impact. In: : . Paper presented at Wear of materials 21 st international conference on wear of Materials, 26-30 Mars Long Beach CA.
Open this publication in new window or tab >>Damage mechanisms for tools used in applications subjected to combined wear and impact
2017 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kau:diva-63710 (URN)
Conference
Wear of materials 21 st international conference on wear of Materials, 26-30 Mars Long Beach CA
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-05-20Bibliographically approved
Gåård, A. (2017). Environmental and Application Factors in Solid Friction: Friction in Metal Forming. In: ASM Handbook vol. 18: Friction, Lubrication, and Wear Technology. ASM International
Open this publication in new window or tab >>Environmental and Application Factors in Solid Friction: Friction in Metal Forming
2017 (Swedish)In: ASM Handbook vol. 18: Friction, Lubrication, and Wear Technology, ASM International, 2017Chapter in book (Refereed)
Place, publisher, year, edition, pages
ASM International, 2017
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kau:diva-63695 (URN)1627081410 (ISBN)
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-05-20Bibliographically approved
Gåård, A. (2017). Införandet av Computer Based Mathematics (CBM) i ingenjörsutbildningar. In: : . Paper presented at Den 6:e utvecklingskonferensen för Sveriges ingenjörsutbildningar: Hållbar ingenjörsutbildning - kvalitet och långsiktighet. Göteborg, Chalmers tekniska högskola, 22-23 november 2017.
Open this publication in new window or tab >>Införandet av Computer Based Mathematics (CBM) i ingenjörsutbildningar
2017 (Swedish)Conference paper, Published paper (Refereed)
National Category
Educational Sciences
Identifiers
urn:nbn:se:kau:diva-63703 (URN)
Conference
Den 6:e utvecklingskonferensen för Sveriges ingenjörsutbildningar: Hållbar ingenjörsutbildning - kvalitet och långsiktighet. Göteborg, Chalmers tekniska högskola, 22-23 november 2017
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2018-12-20Bibliographically approved
Hämäläinen, P., Hallbäck, N., Gåård, A. & Lestelius, M. (2017). On the determination of transverse shear properties of paper using the short span compression test. Mechanics of materials (Print), 107, 22-30
Open this publication in new window or tab >>On the determination of transverse shear properties of paper using the short span compression test
2017 (English)In: Mechanics of materials (Print), ISSN 0167-6636, E-ISSN 1872-7743, Vol. 107, p. 22-30Article in journal (Refereed) Published
Abstract [en]

The present paper explores the short span compression tester (SCT) as a means to experimentally determine the transverse shear moduli of paper. These moduli, which are known to be difficult to determine by any other means, are of importance for the behavior of paper during tissue manufacturing and in the converting and embossing of paperboard. Testing was conducted on paper of two different grammages both in MD and in CD. By applying the Timoshenko-Engesser theory for buckling of shear compliant materials, estimates of the transverse shear moduli were obtained through the measured SCT values and standard measurements of the Young's modulus and the thickness. These estimates were evaluated by detailed FE-analyses of the SCT setup incorporating initial geometrical imperfections representative for real test conditions. It was found that the Timoshenko-Engesser theory gives estimates of the transverse shear moduli that are within an accuracy well applicable for most engineering purposes. The results suggest that the method is at least as accurate as any other, more involved, method that could be used for the purpose.

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Paper, Pulp and Fiber Technology
Research subject
Chemical Engineering
Identifiers
urn:nbn:se:kau:diva-63022 (URN)10.1016/j.mechmat.2017.01.012 (DOI)000397366100002 ()
Projects
VIPP
Funder
Knowledge Foundation
Available from: 2017-09-11 Created: 2017-09-11 Last updated: 2019-07-09Bibliographically approved
AlMotasem, A. T., Bergström, J., Gåård, A., Krakhmalev, P. & Holleboom, T. (2017). Tool microstructure impact on the wear behavior of ferrite iron during nanoscratching: An atomic level simulation. Wear, 370-371, 39-45
Open this publication in new window or tab >>Tool microstructure impact on the wear behavior of ferrite iron during nanoscratching: An atomic level simulation
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2017 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 370-371, p. 39-45Article in journal (Refereed) Published
Abstract [en]

In the present work, molecular dynamics simulations were used to investigate the impact of the tool microstructure on the wear behavior of ferrite workpiece during nanoscratching. The tool microstructure was modified by varying the carbide (cementite) contents. The simulation results show that dislocations are the primary mechanism for plastic deformation of the workpiece material. It is found that total dislocation length varies significantly depending on the carbide content in the tool. Furthermore, other tribological phenomena were also observed to depend on the carbide contents. For example, the average value of frictional forces decreased while the normal force increases with increasing carbide contents, and hence the friction coefficient was decreased. Additionally, the shape and size of lateral and frontal pileups are lowered. The structural analysis of the pileup region reveals the loss of long range order and start of amorphisation. The temperature distribution of the pileup regions showed an increase of the pileup temperature when carbide is added into tool. The wear volume is considerably reduced when the carbide content increases. The average scratch hardness was found to decrease and the result was analyzed with the theoretical Taylor hardening model.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Molecular dynamics, Carbide, Wear volume, Dislocation, Pileup
National Category
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-55215 (URN)10.1016/j.wear.2016.11.008 (DOI)000392776300005 ()
Available from: 2017-06-20 Created: 2017-06-20 Last updated: 2019-10-21Bibliographically approved
Gåård, A. (2017). Wear mechanisms in thread joints of rock drill, a case study. In: : . Paper presented at Wear of materials 21st International Conference on Wear of Materials 26-30 mars Long Beach CA.
Open this publication in new window or tab >>Wear mechanisms in thread joints of rock drill, a case study
2017 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:kau:diva-63709 (URN)
Conference
Wear of materials 21st International Conference on Wear of Materials 26-30 mars Long Beach CA
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-05-20Bibliographically approved
Almotasem, A., Bergström, J., Gåård, A., Krakhmalev, P. & Holleboom, T. J. (2016). A molecular dynamic study on the influence of carbide particles in ferrite on material transfer during nanoscratching of ferritic iron. In: Simancik, Frantisek (Ed.), Proceedings of the 10th International Tool Conference: TOOL, 10th International TOOL Conference : 04th to 07th October 2016, Bratislava, Slovakia. Paper presented at 10th TOOL Conference 2016 - TOOL 2016, Bratislava, Slovakia.
Open this publication in new window or tab >>A molecular dynamic study on the influence of carbide particles in ferrite on material transfer during nanoscratching of ferritic iron
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2016 (English)In: Proceedings of the 10th International Tool Conference: TOOL, 10th International TOOL Conference : 04th to 07th October 2016, Bratislava, Slovakia / [ed] Simancik, Frantisek, 2016Conference paper, Published paper (Refereed)
National Category
Materials Engineering
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-63702 (URN)9783200047860 (ISBN)
Conference
10th TOOL Conference 2016 - TOOL 2016, Bratislava, Slovakia
Available from: 2017-09-14 Created: 2017-09-14 Last updated: 2019-10-21Bibliographically approved
AlMotasem, A. T., Bergström, J., Gåård, A., Krakhmalev, P. & Holleboom, T. (2016). Adhesion between ferrite iron-€“iron/cementite countersurfaces: A molecular dynamics study. Tribology International, 103, 113-120
Open this publication in new window or tab >>Adhesion between ferrite iron-€“iron/cementite countersurfaces: A molecular dynamics study
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2016 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 103, p. 113-120Article in journal (Refereed) Published
Abstract [en]

The adhesive properties of Fe(110)/Fe(110) and Fe3C(001)/Fe(110) countersurfaces have been investigated by using classical molecular dynamics simulations. The simulation results show that Fe3C/Fe exhibits a relatively lower adhesion compared to the Fe/Fe. Additionally, the temperature dependence of the adhesive properties between 300–700 K has been examined. The results demonstrate that, with increasing the temperature, the values of the adhesion force and the work of adhesion continuously decrease in the case of Fe3C/Fe; they initially slightly increase up to 500 K then decrease in the case of Fe/Fe. Furthermore, the effect of lattice coherency between Fe/Fe has been examined and found to slightly reduce the adhesion. These results explain how carbides improve galling resistance of tool steel observed during dry sliding. 

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Adhesion; Carbides; Iron; Temperature distribution; Tool steel, Adhesive properties; Cementite; Classical molecular dynamics; Commensurability; Galling resistance; Lattice coherency; Temperature dependence; Work of adhesion, Molecular dynamics
National Category
Materials Engineering Nano Technology
Research subject
Materials Engineering
Identifiers
urn:nbn:se:kau:diva-45815 (URN)10.1016/j.triboint.2016.06.027 (DOI)000384777100012 ()2-s2.0-84978120893 (Scopus ID)
Available from: 2016-09-09 Created: 2016-09-09 Last updated: 2019-10-21Bibliographically approved
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