Miran Merhar (Author)

Abstract

V raziskavi smo primerjali vrednosti dinamičnega in statičnega modula elastičnosti 7- in 11-slojne vezane plošče z različnimi kombinacijami usmeritve tkiva posameznih slojev furnirjev. Dinamični modul smo določili iz lastnih frekvenc prvega in drugega nihajnega načina nihanja, kjer smo uporabili Bernoulli-Eulerjevo enačbo, statični modul pa s 4-točkovnim upogibnim testom. Rezultati so pokazali, da ima vezana plošča največji modul elastičnosti pri usmeritvi tkiva zunanjega sloja 0°, nato pa z naraščanjem kota modul pada. Dinamični modul je od statičnega v povprečju za 12 % večji pri 7-slojnih ploščah in za 14 % pri 11-slojnih ploščah. Dinamični modul, določen iz druge lastne frekvence, je v primerih, kjer ni vpliva striga, enak modulu iz prve lastne frekvence, ko pa se pojavi vpliv striga, se modul zniža. Iz omenjene raziskave lahko potrdimo, da sta tako statični kot tudi dinamični način določanja modula elastičnosti vzorcev vezane plošče ustrezna, vendar pa je treba pri dinamičnem načinu preveriti vpliv striga.

Keywords

vezana plošča;bukev;modul elastičnosti;nihanje;statični test;strig;

Data

Language: Slovenian
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL BF - Biotechnical Faculty
UDC: 630*862:539.32
COBISS: 44802563 Link will open in a new window
ISSN: 0024-1067
Parent publication: Les
Views: 1687
Downloads: 334
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: English
Secondary title: Determination of dynamic and static modulus of elasticity of beech plywood
Secondary abstract: The study compared the values of the dynamic and static modulus of elasticity of 7- and 11-layer plywood with different combinations of the grain orientation of individual veneer layers. The dynamic modulus of elasticity was determined from the natural frequencies of the first and second vibration mode using the Bernoulli-Euler equation and the static modulus was determined using the 4-point bending test. The results showed that the plywood has the highest modulus of elasticity at the orientation of the wood grain of the outer layer 0°, and then the modulus decreases with increasing angle. The dynamic modulus is on average 12% higher than the static modulus for 7-layer boards and 14% higher for 11-layer boards. The dynamic modulus determined from the second natural frequency is equal to the modulus determined from the first natural frequency when there is no shear influence, but when the shear influence occurs, the value of the modulus decreases. From the above mentioned investigations it can be confirmed that both static and dynamic methods are suitable for determining the modulus of elasticity of plywood samples, but it is necessary to check the shear influence in the dynamic method.
Secondary keywords: plywood;beech;modulus of elasticity;vibration;static test;shear;
Type (COBISS): Article
Pages: str. 59-69
Volume: ǂLetn. ǂ69
Issue: ǂšt. ǂ2
Chronology: 2020
DOI: 10.26614/les-wood.2020.v69n02a07
ID: 12410075