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Kroon, M., Andreasson, E., Persson Jutemar, E., Petersson, V., Persson, L., Dorn, M. & Olsson, P. (2018). Anisotropic elastic-viscoplastic properties of at finite strains of of injection-moulded low-density polyethylene. Experimental mechanics, 58(1), 75-86
Open this publication in new window or tab >>Anisotropic elastic-viscoplastic properties of at finite strains of of injection-moulded low-density polyethylene
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2018 (English)In: Experimental mechanics, ISSN 0014-4851, E-ISSN 1741-2765, Vol. 58, no 1, p. 75-86Article in journal (Refereed) Published
Abstract [en]

Injection-moulding is one of the most common manufacturing processes used for polymers. In many applications, the mechanical properties of the product is of great importance. Injection-moulding of thin-walled polymer products tends to leave the polymer structure in a state where the mechanical properties are anisotropic, due to alignment of polymer chains along the melt flow direction. The anisotropic elastic-viscoplastic properties of low-density polyethylene, that has undergone an injection-moulding process, are therefore examined in the present work. Test specimens were punched out from injection-moulded plates and tested in uniaxial tension. Three in-plane material directions were investigated. Because of the small thickness of the plates, only the in-plane properties could be determined. Tensile tests with both monotonic and cyclic loading were performed, and the local strains on the surface of the test specimens were measured using image analysis. True stress vs. true strain diagrams were constructed, and the material response was evaluated using an elastic-viscoplasticity law. The components of the anisotropic compliance matrix were determined together with the direction-specific plastic hardening parameters.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Textile, Rubber and Polymeric Materials
Research subject
Technology (byts ev till Engineering), Mechanical Engineering
Identifiers
urn:nbn:se:lnu:diva-68972 (URN)10.1007/s11340-017-0322-y (DOI)000418799700006 ()2-s2.0-85027718634 (Scopus ID)
Available from: 2017-11-23 Created: 2017-11-23 Last updated: 2019-08-29Bibliographically approved
Trischler, J., Sandberg, D. & Dorn, M. (2018). Effect of temperature during vital gluten adhesive preparation and application on shear-bond strength. Journal of Adhesion Science and Technology, 32(4), 448-455
Open this publication in new window or tab >>Effect of temperature during vital gluten adhesive preparation and application on shear-bond strength
2018 (English)In: Journal of Adhesion Science and Technology, ISSN 0169-4243, E-ISSN 1568-5616, Vol. 32, no 4, p. 448-455Article in journal (Refereed) Published
Abstract [en]

If protein-based adhesives are to become a competitive bio-based alternative to synthetic adhesives, the preparation and application methods have to be considerable improved to reduce process time and thereby improve the economy of the adhesive system. The purpose of this study was to investigate the impact of the temperature during preparation and application on the shear-bond strength of an adhesive based on vital gluten for use in wood applications. Vital gluten was used in its natural form and mixed with water of different temperatures (preparation temperature 0 °C or 20 °C), and applied on beech veneer at different temperature (application temperature –10, 20, 60 and 100 °C). Tensile shear-bond strength samples were prepared and tested according to EN 205. The results showed that an increase in veneer temperature during application of the adhesive led to a decrease in the shear-bond strength, but that the preparation temperature of the adhesive had no influence on the strength.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
Keywords
application temperature; bond line; preparation temperature; protein adhesive
National Category
Wood Science
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-67324 (URN)10.1080/01694243.2017.1362807 (DOI)000419353700009 ()2-s2.0-85027024483 (Scopus ID)
Available from: 2017-08-20 Created: 2017-08-28 Last updated: 2019-08-29Bibliographically approved
Dorn, M., Tuvendal, H., Henrik, O. & Serrano, E. (2018). FBBB 4.3 Biobaserade skivmaterial: Experimentella undersökningar. Växjö: Linnéuniversitetet
Open this publication in new window or tab >>FBBB 4.3 Biobaserade skivmaterial: Experimentella undersökningar
2018 (Swedish)Report (Other academic)
Abstract [sv]

Rapporten är del av projektet Framtidens Byggande och Boende (FBBB), delprojekt 4.3 "Biobaserade skivmaterial". I denna rapport presenteras resultatet av de mekaniska drag- och böjprov såsom DTMA analys. Materialet ”Durapulp”, som tillverkas av Södra, är referensmaterialet i delprojektet. Provkroppar av Durapulp producerades med olika tillverkningsmetoder för att se skillnader i beteenden. Referensmaterialen är trä-baserade skivmaterial som anses vanligt förekommande i byggskeendet.

Place, publisher, year, edition, pages
Växjö: Linnéuniversitetet, 2018. p. 42
Keywords
biobaserad komposit, mekanisk provning, PLA, pappersmassa
National Category
Bio Materials Composite Science and Engineering
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-79222 (URN)
Projects
Framtidens biobaserade byggande och boende
Funder
Vinnova, 2015-05852
Available from: 2019-01-15 Created: 2019-01-15 Last updated: 2019-08-19Bibliographically approved
Schweigler, M., Bolmsvik, Å. & Dorn, M. (2018). Static and dynamic properties of connections in timber-frame structures: BOOST + FBBB project. Linnaeus University, Faculty of Technology Department of Building Technology
Open this publication in new window or tab >>Static and dynamic properties of connections in timber-frame structures: BOOST + FBBB project
2018 (English)Report (Other academic)
Abstract [en]

Connections play an important role in timber frame structures, especially when approaching the market of multi-story buildings. Two questions faced by practitioners were studied: for the first is the deformation behavior of such structures, where connections between wall and floor elements play an important role for the global stability of the timber structure. For the second is the sound transmission within elements of high importance, particularly timber building systems face challenges. For that reason, the static and dynamic behavior of such connections was studied in a joined experimental program. Two different building systems were investigated in 13 different test setups of how a floor and wall elements were connected to each other. By adjusting connection elements, the influence of various parameters on the dynamic and static behavior was studied. Sound/vibration transmission over the wall-floor connection was the special interest of the dynamic study. The floor element was excited by a shaker, and the response of floor and wall element was measured by accelerometers. This allowed to identify eigenfrequencies and eigenmodes as well as the damping of the structure and the insertion loss over the connection, respectively. Distinct differences between the building systems of the different producers were seen, while adjustments within building systems influenced only slightly the dynamic behavior. For the static part of the study, the moment-rotation behavior of the wall-floor connection was investigated. Variations of connection designs and layouts were tested to better understand the load-transfer and the mechanical interaction using different connectors and connector arrangements. The nailed connection between vertical studs and the bottom rail of the wall element was identified as a soft point when loaded by a horizontal force perpendicular to the plane of the wall element. Using screws this connection showed a substantial improvement of the connection strength. Further adjustments on the connector arrangements showed only partly influence on connection stiffness and strength.

Place, publisher, year, edition, pages
Linnaeus University, Faculty of Technology Department of Building Technology, 2018. p. 73
National Category
Building Technologies
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-79461 (URN)
Projects
FBBB Framtidens biobaserade byggande och boendeBOOST - Boende- och bostadsutveckling för stärkt tillväxt
Funder
Vinnova, 2015-05852Swedish Agency for Economic and Regional Growth
Available from: 2019-01-21 Created: 2019-01-21 Last updated: 2019-08-19Bibliographically approved
Murin, J., Aminbaghai, M., Hrabovsky, J., Balduzzi, G., Dorn, M. & Mang, H. A. (2018). Torsional warping eigenmodes of FGM beams with longitudinally varying material properties. Engineering structures, 175, 912-925
Open this publication in new window or tab >>Torsional warping eigenmodes of FGM beams with longitudinally varying material properties
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2018 (English)In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 175, p. 912-925Article in journal (Refereed) Published
Abstract [en]

In this paper, the influence of torsional warping of thin-walled cross-sections of twisted Functionally Graded Material (FGM) beams with a longitudinal polynomial variation of the material properties on their eigenvibrations is investigated, considering the secondary deformations due to the angle of twist. The transfer relations needed for the transfer matrix method are derived. Based on them, the local finite element equations of the twisted FGM beam are established. The warping part of the first derivative of the twist angle, caused by the bimoment, is considered as an additional degree of freedom at the beam nodes. The focus of the numerical investigation, with and without consideration of the Deformation due to the Secondary Torsional Moment (STMDE), is on modal analysis of straight cantilever FGM beams with doubly symmetric open and closed cross sections. The influence of the longitudinal variation of the material properties and the secondary torsion moment on the eigenfrequencies is investigated. The obtained results are compared with the ones calculated by a very fine mesh of standard solid and warping beam finite elements.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Functionally graded material beams, Longitudinally varying material properties, Non-uniform torsion, Warping torsional eigenvibrations, Deformation due to the secondary torsion moment
National Category
Materials Engineering
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-78736 (URN)10.1016/j.engstruct.2018.08.048 (DOI)000448101300060 ()2-s2.0-85052648226 (Scopus ID)
Available from: 2018-11-08 Created: 2018-11-08 Last updated: 2019-08-29Bibliographically approved
Trischler, J., Sandberg, D. & Dorn, M. (2018). Vital gluten for particleboard production: effect of wood-particle moisture on board properties. Forest products journal, 68(2), 127-131
Open this publication in new window or tab >>Vital gluten for particleboard production: effect of wood-particle moisture on board properties
2018 (English)In: Forest products journal, ISSN 0015-7473, Vol. 68, no 2, p. 127-131Article in journal (Refereed) Published
Abstract [en]

The growing environmental awareness is leading to an increased interest in the use of bio-based adhesives and proteins such as vital gluten. The purpose of this study was to investigate the influence of the wood-particle moisture content, water application and press time on the internal bond strength, thickness expansion and thickness swelling of particleboards glued with vital gluten. Green and dried wood particles with similar moisture contents were achieved through drying or water addition and were blended with vital gluten powder and pressed for 1 to 3 minutes. The results show that not only the pressing time and moisture content, but also the way of achieving the moisture content has a strong impact on the performance of the boards. At comparable moisture content, never-dried (green) particles with high moisture content in combination with a dry adhesive application produced boards which performed better than boards made of dry particles with water addition to simulate liquid adhesive application.

Place, publisher, year, edition, pages
Forest Products Society, 2018
Keywords
bio-based adhesive, internal bond strength, particle configuration, thickness swelling.
National Category
Wood Science Composite Science and Engineering
Research subject
Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-69428 (URN)10.13073/FPJ-D-17-00036 (DOI)000461045800005 ()2-s2.0-85064054911 (Scopus ID)
Available from: 2017-12-21 Created: 2017-12-21 Last updated: 2019-08-29Bibliographically approved
Karlsson, V., Wärnelöv, M., Dorn, M. & Östman, B. (2017). Brandpåverkan på lastbärande trä-glasväggar. Bygg & teknik, 109(6), 44-47
Open this publication in new window or tab >>Brandpåverkan på lastbärande trä-glasväggar
2017 (Swedish)In: Bygg & teknik, ISSN 0281-658X, Vol. 109, no 6, p. 44-47Article in journal (Other academic) Published
Abstract [sv]

Glas har flera av de egenskaper som eftersöks hos ett bärande material: hög styvhet, hög hållfasthet - och är dessutom transparant! Tillsammans med rätt lim och en träram bildas väggar som klarar stora laster. Linnéuniversitetet i Växjö har forskat inom detta ämne och gjort många tester på glasväggar. Resultaten visar att en bärande glasvägg kan ha lastkapacitet för att klara en bostadslast för 3-4 våningar. Nu har möjligheterna att även klara brandkraven undersökts i ett examensarbete.

Place, publisher, year, edition, pages
Stockholm: Byggteknikförlaget, 2017
National Category
Building Technologies
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-66121 (URN)
Available from: 2017-09-19 Created: 2017-09-19 Last updated: 2018-05-16Bibliographically approved
Bader, T. K., Schweigler, M., Hochreiner, G., Eberhardsteiner, J., Serrano, E., Dorn, M. & Enquist, B. (2016). Experimental Assessment of the Load Distribution in Multi-Dowel Timber Connections. In: 17th International Conference on Experimental Mechanics, Rhodes, Greece, July 3-7, 2016: . Paper presented at 17th International Conference on Experimental Mechanics, Rhodes, Greece, July 3-7, 2016.
Open this publication in new window or tab >>Experimental Assessment of the Load Distribution in Multi-Dowel Timber Connections
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2016 (English)In: 17th International Conference on Experimental Mechanics, Rhodes, Greece, July 3-7, 2016, 2016Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

An integrative, hierarchically organized testing procedure for the quantification of the load distribution in multi-dowel timber connections is presented herein. The use of contactless deformation measurement systems allowed the combination of test data from single dowel and multi-dowel connections, which gave access to the loads acting on each dowel over the full loading history. As a consequence of the anisotropic material behavior of wood, a nonuniform and progressively changing load distribution among the dowels was found.

National Category
Building Technologies Wood Science
Research subject
Technology (byts ev till Engineering), Civil engineering; Technology (byts ev till Engineering), Forestry and Wood Technology
Identifiers
urn:nbn:se:lnu:diva-56261 (URN)
Conference
17th International Conference on Experimental Mechanics, Rhodes, Greece, July 3-7, 2016
Available from: 2016-08-31 Created: 2016-08-31 Last updated: 2018-05-17Bibliographically approved
Bader, T. K., Schweigler, M., Hochreiner, G., Enquist, B., Dorn, M. & Serrano, E. (2016). Experimental characterization of the global and local behavior of multi-dowel LVL-connections under complex loading. Materials and Structures, 49(6), 2407-2424
Open this publication in new window or tab >>Experimental characterization of the global and local behavior of multi-dowel LVL-connections under complex loading
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2016 (English)In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 49, no 6, p. 2407-2424Article in journal (Refereed) Published
Abstract [en]

The thorough experimental characterization of a dowel-type connection under various combinations of bending moments and normal forces is presented in this study. Double-shear steel-to-timber connections with 12 and 20 mm steel dowels were tested in a 4-point bending test set-up. The load, between the connected steel and wood beams, was transferred by the dowels themselves and also via an additional (passive) contact device, which introduced an eccentric normal force in the timber beam. The behavior of the connections was studied at the global scale of the connection and at the local scale of the individual dowels. A non-contact deformation measurement system was used to assess the changes of the location of the center of relative rotation over the entire loading. At the same time, the head deformations of the individual dowels could be measured, giving a direct indication about the force distribution among the dowels. Due to reinforcement, connections behaved distinctly ductile with a global relative rotation of up to 3°. Pre-stressing of the contact device by a force of 40 kN yielded an even stiffer behavior. For the particular configurations tested herein, the center of rotation was found to be close to the vertical axis of symmetry of the joint and close to the top row of the dowels. Moreover, the superimposed vertical shift of the center of relative rotation in case of a delayed normal force could be quantified. © 2015 RILEM

Keywords
Bending moment and normal force, Center of relative rotation, Dowel connection, Ductility, Reinforcement, Timber, Bending moments, Deformation, Rotation, Wooden beams and girders, 4-point bending tests, Center of rotation, Dowel-type connection, Experimental characterization, Force distributions, Normal forces, Relative rotation, Fasteners
National Category
Building Technologies
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-46196 (URN)10.1617/s11527-015-0657-8 (DOI)000376646900026 ()2-s2.0-84936806518 (Scopus ID)
Available from: 2015-09-10 Created: 2015-09-10 Last updated: 2018-04-25Bibliographically approved
Bader, T. K., Schweigler, M., Serrano, E., Dorn, M., Enquist, B. & Hochreiner, G. (2016). Integrative experimental characterization and engineering modeling of single-dowel connections in LVL. Construction and Building Materials, 107, 235-246
Open this publication in new window or tab >>Integrative experimental characterization and engineering modeling of single-dowel connections in LVL
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2016 (English)In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 107, p. 235-246Article in journal (Refereed) Published
Abstract [en]

In order to be able to realistically and consistently elucidate and subsequently simulate the load displacement behavior of single-dowel connections, the material behavior of the individual components, namely steel dowels and wood, needs to be investigated. The behavior of slotted-in, single-dowel steel-to-laminated veneer lumber (LVL) connections with dowel diameters of 12 and 20 mm is thoroughly discussed here in relation to steel dowel and LVL properties. In addition to connection tests at different load-to-grain directions of 0, 45 and 90, the corresponding embedment behavior of LVL was tested up to dowel displacements of three times the dowel diameter. The material behavior of steel dowels was studied by means of tensile and 3-point bending tests and accompanying finite element simulations. A pronounced nonlinear behavior of the single-dowel connections was observed for all load-to-grain directions. In case of loading perpendicular to the grain, a significant hardening behavior was obvious. Due to the anisotropic material properties of wood, enforcing a loading direction of 45 to the grain resulted in an additional force perpendicular to the load direction which was quantified in a novel biaxial test setup. Thus, a comprehensive and consistent database over different scales of observations of dowel connections could be established, which subsequently was exploited by means of engineering modeling. The comparison of experimental and numerical data illustrates the potential of the engineering modeling approach to overcome drawbacks of current design regulations, which are unable to appropriately predict stiffness properties of dowel connections. Moreover, the quasi-elastic limit of dowel connections was calculated and discussed by means of the model. (c) 2016 Elsevier Ltd. All rights reserved.

Keywords
Dowel connection, Engineering modeling, Anisotropy, Ductility, Stiffness, Reinforcement, Laminated veneer lumber
National Category
Civil Engineering
Research subject
Technology (byts ev till Engineering), Civil engineering
Identifiers
urn:nbn:se:lnu:diva-51061 (URN)10.1016/j.conbuildmat.2016.01.009 (DOI)000370308000024 ()2-s2.0-84954319869 (Scopus ID)
Available from: 2016-03-18 Created: 2016-03-18 Last updated: 2018-05-17Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-1181-8479

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