WOOD RESEARCH Volume 65, Number 4, 2020
Katarína Dúbravská, Ľudmila Tereňová, and Jaroslava Štefková

CLT construction performance under thermal loading

The paper deals with testing fire resistance of a vertical wooden building construction made of CLT panels subjected to the medium-scale test of the fire resistance. A model test of fire resistance with the ceramic radiation panel as the radiation heat source, with achievable temperature of radiation surface of 935°C at maximum was used. The aim of the experiment was to assess the experiment sample whether it meets the request of the thermal insulation and integrity under thermal loading of the model fire for 30 min. The test resulted in the increase of temperatures on observed thermocouples and assessment of the integrity on the unexposed side of the CLT panel. The construction clearly resisted the effects of the radiation heat during 30 min and maintained the observed criteria of fire resistance. Charred layer of the CLT panel created on the surface of the exposed side in the thickness of 20 mm inhibited the heat transfer into the further layers of construction.

WOOD RESEARCH Volume 64, Number 3, 2019
Peter Koleda, Štefan Barcík, Ľubomír Naščák, Ján Svoreň, and Jaroslava Štefková

Cutting power during lengthwise milling of thermally modified oak wood

The paper presents experimental results of cutting power of thermally modified and non-modified hardwood of Summer oak (Quercus robur) during lengthwise milling. The process of heat treatment was performed in the atmosphere of superheated steam, at temperature 210ºC. Cutting power was determined during milling of the radial surface of modified and non-modified samples. It was calculated as the difference of power consumption by a milling machine during wood machining and at idling. Several cutting regimes were tested by combining different values of rotation speed, feed speed, rake angle and constant cutting depth ae = 1 mm. The values of cutting power are approximately the same at the kinematic angle of the tool head γ = 15°, 30°; there are bigger differences for γ = 20°. The decline of cutting power in the thermally modified (210°C) oak wood machining compared to natural oak wood is 21.7% ÷ 22.2% at the cutting speed vc =40 m. s-1.