Press Mold Characterization to Ensure the Integrity of the Front Face of the Bonding Relief Plywood

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UDС

674-419.3

DOI:

10.17238/issn0536-1036.2015.3.77

Abstract

Relief plywood is glued in press mold with gage interference, what results in a picture on its front face. The practice of such plywood production shows that front sheet is destroyed in a number of cases of gluing veneer sheet. Therefore determination of press mold parameters ensuring integrity of the production is of special value. The article considers a method used to calculate stress-strain condition of a package of veneer layers. Physical non-linear behavior of materials, geometric nonlinearity caused by the influence of great displacements on geometry of the considered system and structural nonlinearity related to variability of contact between press mold and veneer sheet is considered. Deformation of five-layer package of plywood, produced from birch veneer is analyzed. Whereas the upper traverse plate and press mold, located above veneer layers, are considered absolutely rigid. Kinematic loading of the package is considered in plane flat deform condition. Calculation is made in a nonstationary formulation with the finite elements method. According D’Alembert’s principle a system of nonlinear differential equations, describing dynamic balance for a sampled object is built. Solution of the initial-value problem is based on prerequisite of Newmark method about constant values of accelerations at every stage of integration. System geometry in deformed condition has been taken into account for realization of such approach to study of non-linear process. Whereas tangential stiffness matrix of finite element model, calculated as a sum of tangential stiffness matrix of infinitesimal deformation, built with regard to physical and structural non-linearity and initial stress matrix has been used. Characteristics of stress-strain condition of gluing layers have been determined on the base of mathematical modeling of the plywood sheet loading with regard to application of rectangular and round ed edges of the press mold in the place where height of its working surface is changed. It has been established that areas of contact of veneer layers with edges of the press mold are the most dangerous zones in terms of maximum stresses. Parameters of considered technological process that enable obtaining required reliefs on the surface of fabricated produce, keeping its integrity have been determined.

Authors

I.N. Serpik, Doctor of Engineering, Professor А.V. Alekseytsev, Candidate of Engineering, Associate Professor А.А. Lukash, Candidate of Engineering, Associate Professor

Affiliation

Bryansk State Academy of Engineering and Technology, Stanke Dimitrov pr., 3, Bryansk, 241037, Russia; e-mail: iserpik@online.debryansk.ru

Keywords

plywood, press-mold, bonding, relief, strength, differential equations, nonlinearity, parameters.

References

1. Borovikov A.M., Ugolev B.N. Spravochnik po drevesine [Wood Reference Guide]. Moscow, 1989. 296 p. 2. Kulikov V.A., Chubov A.B. Tekhnologiya kleenykh materialov i plit [Technology of Glued Materials and Plates]. Moscow, 1984. 344 p. 3. Lukash A.A. Tekhnologicheskie osobennosti proizvodstva rel'efnoy fanery [Tech-nological Characteristics of Producing Relief Plywood]. Lesnoy zhurnal, 2008, no. 5, pp. 92–96. 4. Lukash A.A. Deformatsii drevesiny pri skleivanii rel'efnoy fanery [Wood Defor-mations at Glueing Relief Plywood]. Lesnoy zhurnal, 2011, no. 2, pp. 119–123. 5. Lukash A.A. Ustroystvo dlya skleivaniya drevesnykh sloistykh materialov [Device Used to Glue Wooden Laminated Materials]. Patent RF, no.200013237/13. 6. Serpik I.N., Leletko A.A., Alekseytsev A.V., Milakova A.A., Gorbachev S.M. Op-timal'nyy sintez ramnykh metallicheskikh karkasov grazhdanskikh zdaniy s uchetom zaproektnykh vozdeystviy [Optimum Synthesis of Framed Metal Structures of Civil Build-ing with Regard of Emergency Actions]. Teoriya i praktika rascheta zdaniy, sooruzheniy i elementov konstruktsiy. Analiticheskie i chislennye metody [Theory and Practice of Calcula-tion for Buildings, Constructions and Elements of Structures. Analytical and Numerical Methods. Collected Papers]. Moscow, 2009, pp. 263–273. 7. Zienkiewicz O.C., Taylor R.L. The finite element method for solid and structural mechanics. Sixth edition. Oxford: Elsevier Butterworth-Heinemann. 2005. 631 p.