WOOD RESEARCH Volume 61, Number 3, 2016
Fedyukov Vladimir Ilyich, Saldaeva Ekaterina Yurevna, Tsvetkova Ekaterina Mikhailovna, and Chavchavadze Evgenia Savelevna

Resonance wood microstructure peculiarities

In researches there are contradictory conclusions about interconnection between macrostructural and acoustic characteristics of sounding timber. Unfortunately, there are only a few works of such kind and all of them are of sporadic nature, which give evidence of necessity to continue such researches both at the level of macrostructure and microstructure. The aim of the research is to reveal the peculiarities of sounding timber microstructure, thanks to which it combines two incompatible, at first sight, parameters: High modulus of elasticity (rigidity) and low density. As a result, sounding timber differs from ordinary one in its unique acoustic characteristics, especially in delicacy and timber of sounding. The research results were obtained through applying an electronic scanning microscope to 360 constant and temporary specimens. For this purpose, 800 timber cuts were made in transversal, radial and tangential directions of a tree stem. Besides, macerated material was used to define early and late tracheids length. In the course of the experiment the increment layers width, the number of tracheids in a radial row of early wood, the number of tracheids in a radial row of late wood, the radial and tangential diameters of early and late tracheids, the thickness of tracheids radial and tangential walls in early and late wood, the quantity of vertical resin ducts and their diameter, the height and number of plies in linear (single-row) rays, the height and number of plies in fusiform rays, the diameter of a horizontal resin duct, the quantity and diameter of rounded bordering pores on tracheid walls were studied. The research results revealed a number of differentiating characteristics of sounding spruce timber microstructure.

WOOD RESEARCH Volume 62, Number 4, 2017
Vladimir Fedyukov, Ekaterina Saldaeva, and Maria Chernova

Different ways of elastic modulus comparative study to predict resonant properties of standing spruce wood

Resonant method of determining modulus of elasticity and shift and decrement of fluctuations’ operates in Russia to determine elastic-viscous properties of wood (GOST 16483.31-197474). The method is destroying and demanding much time and expenses for manufacturing pre-production models in the form of rectangular bar sized 20×20×300 mm, which requires tree cutting down, severing, sawing, etc.; as a consequence, it has not found wide implementation in the practice of research and, especially, selection of qualitative material for musical instruments manufacturing. The work objective is to conduct basic research on revealing a more effective and precise non-destructive method for identifying Young’s dynamic modulus of elasticity as a basic criterion of standing spruce-tree resonant wood quality with the aim of its selection at an early age and creation of perspective object for woodworking with reference to musical instruments manufacture.

WOOD RESEARCH Volume 63, Number 5, 2018
Vladimir Ilyich Fedyukov, Mikhail Vladimirovich Boyarsky, Ekaterina Yuryevna Saldaeva, Maria Sergeyevna Chernova, and Vasiliy Yuryevich Chernov

Dependence of spruce wood resonance properties on its chemical composition

Nowadays there are no reasoned scientific data on inter relation of resonant properties of spruce-tree wood and its chemical composition. Thus the purpose of the study was to reveal the features of sonorous spruce in view of the content of basic organic substances in their timber. 20 model trees at the age of 180-190 years were selected as material for studies in taiga woods in the north of Kirov region of Russia. Special 0.5 m long blocks were made from each model tree at height of 1.3 m. Standard 20×20×300 mm samples were made from those blocks. Test samples were kept at room dry conditions for 2 years. After that dendro acoustic studies were carried out on them to define acoustic constant in different directions with respect to timber fibers. Further the percentage of cellulose, lignin, extractives and ashes in them was defined applying standard techniques. As a whole the chemical composition of spruce tree resonant wood lies approximately within the same limits as in common wood of the breed given. However significant influence of cellulose on a longitudinal acoustic constant and lignin on a radial constant is revealed. Joint influence of lignin and cellulose on a tangential constant is found out, the influence of lignin in the latter case being dominant. Continuation of fundamental research in this field has great cognitive value for revealing the nature of unique acoustic properties formation in sonorous spruce wood. Such studies acquire special topicality when dealing with outstanding violins as well as the wood kept for many decades in old buildings subject to demolition.