Solid wood joints by in situ welding of structural wood constituents

Gfeller, B.; Pizzi, A.; Zanetti, Michela; Properzi, M.; Pichelin, Frédéric; Lehmann, Mario; Delmotte, Luc

doi:10.1515/hf.2004.007

Cited by 32 publications

(38 citation statements)

References 5 publications

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“…The adhesion is generated in the interface from the thin layer of molten wood substances after solidification (Gfeller et al 2003). The mechanical performance of the process is frequently investigated by varying the parameters, such as welding time and pressure, amplitude of vibration, and surface quality, and by submitting the welded specimens to shear test according to DIN-EN (2003) 205 (Gfeller et al 2003(Gfeller et al , 2004Ganne-Chédeville et al 2005;Ganne-Chédeville 2008). Ganne-Chédeville et al (2008) observed the behavior of double cantilever beam (DCB) specimens and measured the critical energy release rate (G Ic ) of a welded joint.…”

Section: Introductionmentioning

confidence: 99%

Influence of the moisture content on the fracture characteristics of welded wood joint. Part 1: Mode I fracture

2013

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Friction welding is a joining technique for wood materials. The positive aspects of this technique are the speed of processing and the absence of chemical or mechanical agents, but the welded joints are not water resistant. To understand better the effect of moisture on the fracture behavior of welded joints, their fracture characteristics have been investigated. The double cantilever beam specimens were tested, which permit to compute the mode I energy release rate of a welded joint. The results confirm the negative effect of moisture on the fracture properties of the joint. The data concerning the maximal tensile strength of the joining material were collected by uniaxial tests and implemented in a finite element model to establish a cohesive law, which describes the behavior of welded pieces in terms of moisture content.

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Section: Introductionmentioning

confidence: 99%

Influence of the moisture content on the fracture characteristics of welded wood joint. Part 1: Mode I fracture

2013

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“…Linear friction welding, i.e., welding with a reciprocating movement, is commonly employed in the thermoplastics and metals industries, and it has shown potential in wood-to-wood connections as well (Sutthoff et al 1996). To highlight the key phenomena within the friction welding process for wood, first certain wood components soften to the point that they even melt and evaporate; second, the components and derivatives form an interphase between the two pieces of wood to be joined by a high-density composite of entangled wood fibres drowned into a matrix of molten wood-intercellular material, such as lignin and hemicelluloses (Gfeller et al 2004;Mansouri et al 2009). The friction welding of wood is characterised by a rapid increase in temperature from ambient up to 220 °C or 450 °C in linear or orbital friction welding, respectively (Stamm et al 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Welded joints produced by Gfeller et al (2003Gfeller et al ( , 2004) yielded a tensile-shear strength of more than 10 MPa in beech (Fagus sylvatica L.) and 2 MPa in spruce (Picea abies L. Karst.)…”

Section: Introductionmentioning

confidence: 99%

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

Ruponen¹,

Čermák²,

Rhême³

et al. 2015

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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.

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“…[7,10] Wood welding, in the context presented herein, refers to the vibrational bonding method in which only wood is used.…”

Section: Origin and Brief History Of Wood Weldingmentioning

confidence: 99%

“…There are two main branches of wood welding: planar [7,[9][10][11][14][15][16][17][18][19][20][21][22][23][24][25][26][27] and rotational [9,[28][29][30][31][32][33][34][35][36][37][38][39]. Planer is further broken down further into linear vibrational [7,[9][10][11][14][15][16][17][18][19][20][21][22][23][24] and orbital [25][26][27].…”

Section: Planar (Surface) Wood Weldingmentioning

confidence: 99%

Investigating Wood Welding Parameters Using a Prototype Welding Machine

Melin

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Investigating Wood Welding Parameters Using a Prototype Welding Machine Timothy MelinUnderstanding how different processing variables influence wood welded bonds is vital if the technique will ever be used to create engineered lumber without using adhesives. A variation of vibration welding, wood welding uses pressure and friction to bond materials together. During welding, heat causes a softening in the wood, a naturally occurring composite material. This softening leads to fiber entanglement and a bond forms upon cooling.The goal of this research was to investigate several processing aspects of the wood welding procedure. A prototype wood welding machine, designed and fabricated from the ground up, was used to investigate the effects of various welding parameters using birch wood. Wood welds were evaluated on the basis of bond coverage and ultimate shear strength.Four experiments were performed: welding frequency and duration interaction, grain orientation effects, alternative welding completion metrics, and strength development over time. During the wood welding process, three distinct phenomena were repeatedly observed: smoke creation, welding residue formation, and an audible pitch change. The presence of each was recorded for every wood welded specimen and used later in additional data analysis. Investigating each of the welding phenomena was done in an attempt to better characterize when fusion was achieved at the weld interface. v ImageTool, an image analysis software package, was used to investigate and quantify the often irregular bonds exposed after shear fracture. The results of the various welding variables were analyzed on the basis of shear strength and bond uniformity.From the birch samples, it was shown that better bonds result from lower welding frequencies and longer welding durations. The grain orientation analysis demonstrated that welding orientation marginally affects the average shear strength of the wood weld.The data from the alternative welding metrics suggests that welding time is not a quality indicator of welding completion (bond coverage). The strength development trials confirmed previous research; wood welds obtain most of their strength in a relatively short period of time.Douglas fir and poplar both proved to be weldable for the first time, but they were sufficiently weaker than birch. When welding was attempted with Douglas fir under similar pressures used for birch, Douglas fir samples would commonly "washboard."With reduced welding pressure, Douglas fir formed wood welds more easily.

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Solid wood joints by in situ welding of structural wood constituents

Cited by 32 publications

References 5 publications

Influence of the moisture content on the fracture characteristics of welded wood joint. Part 1: Mode I fracture

Influence of the moisture content on the fracture characteristics of welded wood joint. Part 1: Mode I fracture

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

Investigating Wood Welding Parameters Using a Prototype Welding Machine

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