Experimental Evaluation of Strength of End Joints with Rectangular Pressed Fingers

Complete text of the article:

Download article (pdf, 1.4MB )

UDС

674.028.9+674.049.2

DOI:

10.37482/0536-1036-2020-3-128-142

Abstract

End jointing of wooden blanks is widely distributed in the manufacture of wood products. The most commonly used splicing technology on finger joints with pointy fingers has a number of drawbacks, including the presence of waste and an expensive cutting tool. We proposed an alternative type of end jointing with multiple rectangular tenons made by pressing. Commercialization of the new splicing method requires confirmation of its high quality. The main quality indicator of adhesive joint is its strength. The aim of the study is an experimental evaluation of the bending strength and tensile strength of end joints with rectangular pressed fingers (case study of pine wood blanks). The joints of two types: A and B, with a pitch of 4.2 and 8.2 mm and depth of mortises of 10 and 20 mm, respectively, were studied. The strength of the samples was determined taking into account the requirements of the Russian State Standards GOST 15613.4 and GOST 15613.5. In order to evaluate the quality of joints, we used the indicator “relative strength”; it is the ratio of the joint strength to the solid wood strength. Statistical processing was carried out both by data groups, and for each size and each test type separately. This allowed us to establish the average values of strength for each individual group of samples, as well as to obtain a statistically valid joint evaluation of some indicators. Joints of type A with small fingers showed better results in tensile strength (59.5 %) compared to joints of type B (53.2 %). No statistically significant effect of the joint type was revealed, when processing the results of bending tests in the studied range. Therefore, the average bending strength (80.2 %) characterizes both types of joints. Moreover, the strength of these two types of joints with sufficient reliability can be characterized by the average tensile strength (56.4 %). At the same time, both types of joints correspond in strength to the standard requirements to the products with adhesive end joints. The test results vary in a relatively narrow range, which indicates a stable quality of adhesive joints with rectangular fingers made by pressing. This study demonstrates the possibility of using rectangular pressed fingers for the manufacture of joints based on them.

Authors

О.A. Rubleva¹, Candidate of Engineering, Assoc. Prof.; ResearcherID: Q-7239-2017,
ORCID: https://orcid.org/0000-0003-0756-6130
A.G. Gorokhovsky², Doctor of Engineering, Prof.; ResearcherID: O-6030-2018,
ORCID: https://orcid.org/0000-0001-8847-8217

Affiliation

¹Vyatka State University, ul. Moskovskaya, 36, Kirov, 610000, Russian Federation; e‑mail: olga_ru@vyatsu.ru
²Ural State Forest Engineering University, ul. Sibirskiy trakt, 37, Yekaterinburg, 620100, Russian Federation; e-mail: goralegr@yandex.ru

Keywords

finger joints, splicing, rectangular finger, wood pressing, bond strength of a joint

For citation

Rubleva O.A., Gorokhovsky A.G. Experimental Evaluation of Strength of End Joints with Rectangular Pressed Fingers. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 3, pp. 128–142. DOI: 10.37482/0536-1036-2020-3-128-142

References

1. Bartashevich A.A., Trofimov S.P. Furniture Construction. Minsk, Sovremennaya shkola Publ., 2006. 336 p.
2. Volynskiy V.N. Technology of Glued Materials. Saint Petersburg, PROFIKS Publ., 2008. 392 p.
3. GOST 15613.4–78. Glued Massive Wood. Methods for Determining the Ultimate Strength of Serrate Glued Joints in Static Bending. Moscow, Izdatel’stvo standartov, 1999. 7 p.
4. GOST 15613.5–79. Glued Massive Wood. Method for Determination of Ultimate Tensile Strength of Finger Glued Joints. Moscow, Izdatel’stvo standartov, 1999. 7 p.
5. GOST 16483.23–73. Wood. Method for Determination of Ultimate Strength in Tension along the Grain. Moscow, Izdatel’stvo standartov, 1999. 4 p.
6. GOST 16483.3–84 (ST SEV 390–76). Wood. Method of Static Bending Strength Determination. Moscow, Izdatel’stvo standartov, 1999. 7 p.
7. GOST 16588–91 (ISO 4470–81). Sawn Products and Wooden Details. Methods for Determining Moisture Content. Moscow, Standartinform Publ., 2009. 6 p.
8. GOST 20850–2014. Wooden Glued Load Bearing Structures. General Specifications. Moscow, Standartinform Publ., 2015. 18 p.
9. GOST 24700–99. Windows of Wood with Glassing Units. Specifications. Moscow, Gosstroy Rossii, GUP TsPP Publ., 2000. 55 p.
10. GOST 30972–2002. Glue Wood Billets and Details for Windows and Doors. Specifications. Moscow, Gosstroy Rossii, GUP TsPP Publ., 2003. 30 p.
11. GOST 33080–2014. Timber Structures. Strength Classes of Structural Sawn Timber and Methods of Its Determination. Moscow, Standartinform Publ., 2015. 14 p.
12. GOST 33081–2014. Wooden Glued Bearing Structures. Strength Classes of Structures Elements and Methods for Its Determination. Moscow, Standartinform Publ., 2015. 10 p.
13. Zhukov V.P. Wood Gluing Technology. Voronezh, VGLTI Publ., 1981. 79 p.
14. Rubleva O.A. Method of Forming Finger Joints in Wood Blanks. Patent RF no. RU 2471614 C1, 2013.
15. Plastinin S.N. Manufacturing of Glued Products at Sawmills. Moscow, Lesnaya promyshlennost’ Publ., 1983. 48 p.
16. Rubleva O.A. Formation of Rectangular Tenons by Mechanical Pressing Method. Lesotekhnicheskiy zhurnal [Forestry Engineering Journal], 2013, no. 4(12), pp. 126–133. DOI: 10.12737/2191
17. Freydin A.S., Vuba K.T. Prediction of the Properties of Adhesive Wood Joints. Moscow, Lesnaya promyshlennost’ Publ., 1980. 224 p.
18. Chubinskiy A.N. Formation of Adhesive Joints of Wood. Saint Petersburg, SPbGU Publ., 1992. 168 p.
19. Ahmad Z., Lum W.C., Lee S.H., Razlan M.A., Wan Mohamad W.H. Mechanical Properties of Finger Jointed Beams Fabricated from Eight Malaysian Hardwood Species. Construction and Building Materials, 2017, vol. 145, pp. 464–473. DOI: 10.1016/j.conbuildmat.2017.04.016
20. Barboutis I., Vasileiou V. Strength of Finger-Jointed Beech Wood (Fagus sylvatica) Constructed with Small Finger Lengths and Bonded with PU and PVAC Adhesives. PROLigno, 2013, vol. 9, iss. 4, pp. 359–364.
21. Biechele T., Chui Y.H., Gong M. Assessing Stiffness on Finger-Jointed Timber with Different Non-Destructive Testing Techniques. The Future of Quality Control for Wood& Wood Products: Proceedings of the Final Conference of COST Action E53, Edinburgh, May 4–7, 2010. Edinburgh, Edinburgh Napier University. 2010, pp. 522–528.
22. Džinčić I., Živanić D. The Influence of Fit on the Distribution of Glue in Oval Tenon/Mortise Joint. Wood Research, 2014, vol. 59, no. 2, pp. 297–302.
23. Hesselbach J., Hoffmeister H.-W., Loohß T. Punching in Industrial Wood Machining: An Alternative Production Process to Drilling. Production Engineering, 2007, vol. 1, iss. 4, pp. 365–370. DOI: 10.1007/s11740-007-0061-5
24. Hu W., Guan H., Zhang J. Finite Element Analysis of Tensile Load Resistance of Mortise-and-Tenon Joints Considering Tenon Fit Effects. Wood and Fiber Science, 2018, vol. 50, no. 2, pp. 121–131.
25. Jokerst R.W. Finger-Jointed Wood Products. Research Paper FPL 382. Forest Products Laboratory. 1981. 26 p.
26. Khelifa M., Celzard A., Oudjene M., Ruelle J. Experimental and Numerical Analysis of CFRP-Strengthened Finger-Jointed Timber Beams. International Journal of Adhesion and Adhesives, 2016, vol. 68, pp. 283–297. DOI: 10.1016/J.IJADHADH.2016.04.007
27. Kishan Kumar V.S., Sharma C.M., Gupta S. Compression and Flexural Properties of Finger Jointed Mango Wood Sections. Maderas. Ciencia y tecnología, 2015, vol. 17, no. 1, pp. 151–160. DOI: 10.4067/s0718-221x2015005000015
28. Konopka D., Gebhardt C., Kaliske M. Numerical Modelling of Wooden Structures. Journal of Cultural Heritage, 2017, vol. 27, pp. S93–S102. DOI: 10.1016/j.culher.2015.09.008
29. Lara-Bocanegra A.J., Majano-Majano A., Crespo J., Guaita M. Finger-Jointed Eucalyptus globulus with 1C-PUR Adhesive for High Performance Engineered Laminated Products. Construction and Building Materials, 2017, vol. 135, pp. 529–537. DOI: 10.1016/j.conbuildmat.2017.01.004
30. Lee S.J., Eom C.D., Kim K.M. Structural Performance of Finger-Jointed Lumber with Different Joint Configurations. Journal of the Korean Wood Science and Technology, 2011, vol. 39, no. 2, pp. 172–178.
31. Likos E., Haviarova E., Eckelman C.A., Erdil Y.Z., Ozcifci A. Effect of Tenon Geometry, Grain Orientation, and Shoulder on Bending Moment Capacity and Moment Rotation Characteristics of Mortise and Tenon Joints. Wood and Fiber Science, 2012, vol. 44, no. 4, pp. 462–469.
32. Mackerle J. Finite Element Analyses in Wood Research: A Bibliography. Wood Science and Technology, 2005, vol. 39, no. 7, pp. 579–600. DOI: 10.1007/s00226-005-0026-9
33. Özçifçi A., Yapıcı F. Structural Performance of the Finger-Jointed Strength of Some Wood Species with Different Joint Configurations. Construction and Building Materials, 2008, vol. 22, iss. 7, pp. 1543–1550. DOI: 10.1016/j.conbuildmat.2007.03.020
34. Prekrat S., Smardzewski J. Effect of Glueline Shape on Strength of Mortise and Tenon Joint. Drvna industrija, 2010, vol. 61, no. 4, pp. 223–228.
35. Ratnasingam J., Scholz F. Optimization of Finger-Jointing in Rubberwood Processing. European Journal of Wood and Wood Products, 2009, vol. 67, iss. 2, pp. 241–242. DOI: 10.1007/s00107-008-0295-8
36. Ryu H.S., Ahn S.Y., Park H.M., Byeon H.S., Kim J.M. Effect of Distance between Finger Tip and Root Width on Compressive Strength Performance of Finger-Jointed Timber. Journal of the Korean Wood Science and Technology, 2004, vol. 32, no. 4, pp. 66–73.
37. Tran V.-D., Oudjene M., Méausoone P.-J. FE Analysis and Geometrical Optimization of Timber Beech Finger-Joint under Bending Test. International Journal of Adhesion and Adhesives, 2014, vol. 52, pp. 40–47. DOI: 10.1016/j.ijadhadh.2014.03.007
38. Vrazel M., Sellers T. The Effects of Species, Adhesive Type, and Cure Temperature on the Strength and Durability of a Structural Finger-Joint. Forest Products Journal, 2004, vol. 54, iss. 3, pp. 66–75.
39. Wilczyński A., Warmbier K. Effect of Joint Dimensions on Strength and Stiffness of Tenon Joints. Folia Forestalia Polonica. Series B – Wood Science, 2003, vol. 34, pp. 53–66.