Technique for determining finish sawing productivity and energy demands under cross-cutting of the frozen wood
Conducting some additional research in energy intensity of the cross-cutting process with gasoline chain saws is of great importance and has already been the subject of our research. Methodological basis for experimental research in determining the basic per-unit cutting work under cross-cutting with gasoline chain saws has been proposed. In particular, an approach, adapted to the research of the cross-cutting process and based on the provisions of the theory of material breakage, has been offered. Possibility of using some basic provisions of material breakage mechanics when finding numerical value of the basic pre-unit cutting work under cross-cutting with gasoline chain saws has been analyzed. Moreover, a relation between wood elastic constants (modulus of wood elasticity under compressing perpendicular the grain, specifically) and pre-unit cutting work under cross-cutting has been shown as a joint effect of negative temperatures and wood moisture content which is made on the wood properties when studying the cross-cutting process should necessarily be taken into consideration. The amount of moisture is distributed unequally along the tree trunk that is why the quantity of the pre-unit cutting work is variable depending on the chain guide position in the saw-cut which, in terms, makes allowances in technique for calculating required cutting capacity and all the data connected with the capacity. The article proposes the model for determining finish sawing productivity under cross-cutting of the frozen wood with gasoline chain saws and with taking into account a variable pattern of the moisture distribution along the tree trunk. According to the results of the research conducted, some general dependencies for determining maximum (which depends on the capacity of a gasoline chain saw) productivity of finish sawing, the saw-cut forming time and the perfect work under cross-cutting of the frozen wood have been received. A variable pattern of the moisture distribution along the tree trunk has been taken into account with the help of the auxiliary linear function. A potential for further research is the integration of the given results into the technique of quality control of wood exploitation by using general evaluation criterion depending on the differences of energy demands to receive the products of wood exploitation and their energy intensity (power effectiveness, received as a difference between energy intensity of the products of wood exploitation and energy demands for all the phases of receiving the products, has been taken as a quality parameter of the process under research).