Kshyvets'kyj B. Predicting the durability of thermoplastic adhesive wood jointing

The object of the study is thermoplastic adhesive wood jointing. The objective of the work is the development of science-based principles of predicting durability of thermoplastic adhesive wood jointing with consideration for patterns of changing stress-strain stare of adhesive jointing depending on the service conditions. The methods of the study are as follows: methods for durability investigations and statistical processing; methods for mathematical modelling of heat-and-mass transfer and finite elements; methods for analytical and numerical solution of linear and differential equations. Scientific novelty: it is for the first time that a mathematical model for predicting durability of thermoplastic adhesive wood jointing has been constructed. It is for the first time that stress-strain state patterns of thermoplastic adhesive wood jointing have been obtained with consideration for natural service condition and moisture transfer in wood. The theoretical studies of mechanism for formation of thermoplastic wood jointing have been further advanced. New patterns of temperature-moisture influence on the physical-and-mechanical properties of thermoplastic adhesive film have been experimentally established. As a result of prolonged experiments, tne dependence, of strength and durability of adhesive wood jointing upon the ambient temperature and air humidity has been further clarified. Established were new patterns of heat-moist treatment effectsion thermoplastic adhesive wood jointing using methods of accelerated experimental investigations, which made it possible to build mathematical relationship for determining the strength of adhesive jointing for hardwood and softwood species. A procedure has been proposed for calculating coefficients for varions wood species their numerical values having been obtained. Theoretical and practical results: a new method for predicting strength and durability of thermoplastic adhesive wood jointing based on mathematical modelling has been proposed, also software has been developed to be used under operating conditions. The degree of implementation: the results of the studies have been implemented in the form of recommendations for technological processes of glueing with thermoplastic adhesives at the enterprise "Fund Production company"; enterprise "Burak"; enterprise "Aned-Ukraine"; Zaklad Produkcyjno-Handlowo-Uslugowy "DREWEX", Poland, Przedsiebiorstwo Produkcyjno-Handlowo-Uslugowy "EXTRANS", Poland.