tailieunhanh - Báo cáo lâm nghiệp: " A contribution to the properties of combined plywood materials"

Tuyển tập những bài báo cáo nghiên cứu khoa học hay nhất được đăng trên tạp chí JOURNAL OF FOREST SCIENCE đề tài: A contribution to the properties of combined plywood materials. | JOURNAL OF FOREST SCIENCE 53 2007 10 483-490 A contribution to the properties of combined plywood materials J. Hrazsky P. Král Faculty of Forestry and Wood Technology Mendel University of Agriculture and Forestry Brno Brno Czech Republic ABSTRACT The paper summarizes the results of institutional research aimed at new types of combined plywood materials. Under pilot plant conditions three variants of combined plywood materials were pressed namely with the layer of fibreglass with a core cork layer and with a cork wear layer on one side of the plywood surface and a cork core. Tests of selected physical and mechanical properties were carried out on these materials including the basic statistical evaluation. Comparisons with plywood materials Multiplex 15 and 20 mm in thickness were also made. Keywords combined plywood density moisture bending strength modulus of elasticity in bending statistical analysis cork core fibreglass surface Plywood is often named as the first from the group of products which are known as engineered wood at present. It was the first material that consisted of disintegrated wood particles in order to create larger and solid composite units firmer and tougher than the sum of the values of their parts Hrazsky Král 2005 . At the end of the 70s and at the beginning of the 80s of the 20th century the principle of plywood allowed the origin of OSB oriented structural boards . Other products from the group of engineered wood are Parallam PSL Intrallam LSL Microllam LVL and TJI beams. These products combine properties of wood also making it possible to use valuable natural resources more economically Bao et al. 1996 Sharp Suddarth 1991 . In addition to their static function combined plywood materials show various special functions . thermal and insulating ones. Through the combination of these two requirements a material originates which is more advantageous compared to the use of separate materials Král Hrazsky 2006 . This advantage consists not .