Influence of Welding Time on Tensile-Shear Strength of Linear Friction Welded Birch (Betula pendula L.) Wood

Abstract

aThe purpose of this work was to determine the optimal welding time for linear friction welding of birch (Betula pendula L.) wood while keeping the other parameters constant and at similar levels compared to other species in a similar density range. Specimens with dimensions of 20 × 5 × 150 mm 3 were welded together, and the influence of welding time (2.5, 3.0, 3.5, and 4.0 s) on the mechanical properties of the specimens was determined. The studies included a tensile-shear strength test as well as visual estimation of wood failure percentage (WFP). Additionally, X-ray microtomographic imaging was used to investigate and characterise the bond line properties as a non-destructive testing method. The highest mean tensile-shear strength, 7.9 MPa, was reached with a welding time of 3.5 s. Generally, all four result groups showed high, yet decreasing proportional standard deviations as the welding time increased. X-ray microtomographic images and analysis express the heterogeneity of the weld line clearly as well. According to the averaged group-wise results, WFP and tensile-shear strength correlated positively with an R 2 of 0.93. An extrapolation of WFP to 65% totals a tensile-shear strength of 10.6 MPa, corresponding to four common adhesive bonds determined for beech.

The role of lignin in wood working processes using elevated temperatures: an abbreviated literature survey

“…The welding processes can be classified as linear, orbital and rotational friction welding (Ruponen et al 2015). In linear welding, the wood samples are joined to each other with a 1.3-2 MPa pressure.…”

“…The quality of a friction welding joint correlates with several welding parameters, such as welding pressure, frequency, time, holding pressure and time, amplitude or displacement, wood species, orientation of the grains, equilibrium moisture content and specimen dimensions, chemical composition etc. (Kanazawa et al 2005;Properzi et al 2005;Ganne-Chédeville et al 2006, 2008Delmotte et al 2009;Omrani et al 2009;Župčić et al 2014;Ruponen et al 2015;Belleville et al 2018;Zhu et al 2019).…”

Tribological mechanisms involved in friction wood welding

“…Notwithstanding, one can notice that similar phenomena and material modifications were observed in both linear, orbital and rotation welding. 5,6 Linear FWW was successfully performed with various wood species including beech 2,10-13 spruce 11, [14][15][16] , oak 9,11,13 pine [17][18][19] , birch 20,21 , poplar 21 , maple 13 , eucalyptus [22][23][24] , bamboo 25,26 , and even heat-treated woods 21,27 . Nevertheless, softwood welding appeared to be more difficult to achieve due to the characteristic cell-wood collapsing effect of these species.…”

“…Second, the contact is maintained under static mechanical loading defined by the holding pressure (HP) and the holding time (HT). Based on numerous studies 2,9,[25][26][27][28][29][30][31][32][33][34]10,[35][36][37]11,15,[20][21][22][23][24] , WP ranges from 0.2 to 4.5 MPa, DA remains close to 2 mm, WT is very short and ranges from 1 to 8 s, HP from 1 to 8 MPa, and HT from 5 to 60 s. The sliding speed is classically expressed as a motion frequency which ranges from 100 to 150 Hz, leading to SV close to 0.6 m.s -1 when considering the associated DA value.…”

Study of the End-grain Butt Joints Obtained by Friction Welding of Moso Bamboo

“…The first aspect of these techniques that is being studied is the bonding of the welded joints. The microstructures of these welding interfaces and the chemical reactions that occur as the welding proceeds were used to explain the inherent mechanism behind the bonding phenomena of the welded joints (Stamm et al 2005;Delmotte et al 2008;Mansouri et al 2010;Belleville et al 2013;Zhang et al 2014a;Ruponen et al 2015). The second aspect of linear-vibration and rotational welding being studied is the optimization of the welding parameters for the different biomaterials and exploration of how they influence the final welding performance.…”